1. Chapter 21 – ASP .NET and Web Services
Outline Introduction Web Services Simple Object Access Protocol (SOAP) and Web Services Publishing and Consuming Web Services Session Tracking in Web Services Using Web Forms and Web Services Case Study: Temperature Information Application User-Defined Types in Web Services

2. 21.2 Web Services Link to service description
Links to web service methods
Fig ASMX file rendered in Internet Explorer.

3. 21.2 Web Services
Fig Service description for a Web service.

4. 21.2 Web Services
Fig Invoking a method of a Web service from a Web browser.

5. 21.2 Web Services
Fig Results of invoking a Web-service method from a Web browser.

6. 21.3 Simple Object Access Protocol (SOAP) and Web Services
Represent arguments named first and second. The value string indicates that they need to be of type string, but in a method call they would be replaced with the argument values.
Name of method
Fig SOAP request for the HugeInteger Web service.

7. Class HugeInteger inherits from System.Web.Services.WebService
1 // Fig. 21.6: HugeInteger.asmx.cs
2 // HugeInteger Web Service. 3
4 using System;
5 using System.Text;
6 using System.Collections;
7 using System.ComponentModel;
8 using System.Data;
9 using System.Diagnostics;
10 using System.Web;
11 using System.Web.Services; // contains Web service related classes 12
13 namespace HugeIntegerWebService
14 {
/// <summary>
/// performs operations on large integers
/// </summary>
[ WebService(
Namespace = "
Description = "A Web service which provides methods that" +
" can manipulate large integer values." ) ]
public class HugeInteger : System.Web.Services.WebService {
// default constructor
public HugeInteger() {
// CODEGEN: This call is required by the ASP .NET Web
// Services Designer
InitializeComponent(); 30
number = new int[ MAXIMUM ]; } 33
HugeInteger.asmx.cs
Set Namespace property of WebService attribute to specify the namespace that the Web service belongs to
Set Description property of WebService attribute to describe the function of the Web Service
Class HugeInteger inherits from System.Web.Services.WebService

8. HugeInteger.asmx.cs 34 #region Component Designer generated code
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent() { }
#endregion 43
/// <summary>
/// Clean up any resources being used.
/// </summary>
protected override void Dispose( bool disposing ) { } 50
// WEB SERVICE EXAMPLE
// The HelloWorld() example service returns
// the string Hello World
// To build, uncomment the following lines
// then save and build the project
// To test this web service, press F5 57
// [WebMethod]
// public string HelloWorld()
// {
// return "Hello World";
// } 63
private const int MAXIMUM = 100; 65
public int[] number; 67
HugeInteger.asmx.cs

9. Indexer for class HugeInteger HugeInteger.asmx.cs
// indexer that accepts an integer parameter
public int this[ int index ] {
get {
return number[ index ]; } 75
set {
number[ index ] = value; } 80
} // end indexer 82
// returns string representation of HugeInteger
public override string ToString() {
StringBuilder returnString = new StringBuilder(); 87
foreach ( int digit in number )
returnString.Insert( 0, digit ); 90
return returnString.ToString(); } 93
// creates HugeInteger based on argument
public static HugeInteger FromString( string integer ) {
HugeInteger parsedInteger = new HugeInteger(); 98
for ( int i = 0; i < integer.Length; i++ )
parsedInteger[ i ] = Int32.Parse(
integer[ integer.Length - i - 1 ].ToString() );
Indexer for class HugeInteger
HugeInteger.asmx.cs

10. Method Add that adds two HugeIntegers
102
return parsedInteger; }
105
// WebMethod that performs integer addition
// represented by string arguments
[ WebMethod ( Description = "Adds two huge integers." ) ]
public string Add( string first, string second ) {
int carry = 0;
112
HugeInteger operand1 = HugeInteger.FromString( first );
HugeInteger operand2 =
HugeInteger.FromString( second );
116
// store result of addition
HugeInteger result = new HugeInteger();
119
// perform addition algorithm for each digit
for ( int i = 0; i < MAXIMUM; i++ ) {
// add two digits in same column
// result is their sum, plus carry from
// previous operation modulus 10
result[ i ] =
( operand1[ i ] + operand2[ i ] ) % 10 + carry;
128
// store remainder of dividing
// sums of two digits by 10
carry = ( operand1[ i ] + operand2[ i ] ) / 10; }
133
return result.ToString();
135
} // end method Add
HugeInteger.asmx.cs
WebMethod attribute specifies that this method may be called by remote client applications
Description property of WebMethod attribute summarizes the function of the method
Method Add that adds two HugeIntegers

11. Method Subtract that subtracts one HugeInteger from another
137
// WebMethod that performs the subtraction of integers
// represented by string arguments
[ WebMethod (
Description = "Subtracts two huge integers." ) ]
public string Subtract( string first, string second ) {
HugeInteger operand1 = HugeInteger.FromString( first );
HugeInteger operand2 =
HugeInteger.FromString( second );
HugeInteger result = new HugeInteger();
148
// subtract top digit from bottom digit
for ( int i = 0; i < MAXIMUM; i++ ) {
// if top digit is smaller than bottom
// digit we need to borrow
if ( operand1[ i ] < operand2[ i ] )
Borrow( operand1, i );
156
// subtract bottom from top
result[ i ] = operand1[ i ] - operand2[ i ]; }
160
return result.ToString();
162
} // end method Subtract
164
// borrows 1 from next digit
private void Borrow( HugeInteger integer, int place ) {
// if no place to borrow from, signal problem
if ( place >= MAXIMUM - 1 )
throw new ArgumentException();
171
HugeInteger.asmx.cs
Method Subtract that subtracts one HugeInteger from another
Helper method Borrow used by method Subtract when 1 needs to be borrowed from the next number

12. 172 // otherwise if next digit is zero,
// borrow from digit to left
else if ( integer[ place + 1 ] == 0 )
Borrow( integer, place + 1 );
176
// add ten to current place because we borrowed
// and subtract one from previous digit -
// this is digit borrowed from
integer[ place ] += 10;
integer[ place + 1 ] -= 1;
182
} // end method Borrow
184
// WebMethod that returns true if first integer is
// bigger than second
[ WebMethod ( Description = "Determines whether first " +
"integer is larger than the second integer." ) ]
public bool Bigger( string first, string second ) {
char[] zeroes = { '0' };
192
try {
// if elimination of all zeroes from result
// of subtraction is an empty string,
// numbers are equal, so return false,
// otherwise return true
if ( Subtract( first, second ).Trim( zeroes ) == "" )
return false;
else
return true; }
204
HugeInteger.asmx.cs
Returns true if the first integer is bigger then the second and false otherwise

13. Returns true if the two integers are equal and false otherwise
// if ArgumentException occurs, first number
// was smaller, so return false
catch ( ArgumentException ) {
return false; }
211
} // end method Bigger
213
// WebMethod returns true if first integer is
// smaller than second
[ WebMethod ( Description = "Determines whether the " +
"first integer is smaller than the second integer." ) ]
public bool Smaller( string first, string second ) {
// if second is bigger than first, then first is
// smaller than second
return Bigger( second, first ); }
224
// WebMethod that returns true if two integers are equal
[ WebMethod ( Description = "Determines whether the " +
"first integer is equal to the second integer." ) ]
public bool EqualTo( string first, string second ) {
// if either first is bigger than second, or first is
// smaller than second, they are not equal
if ( Bigger( first, second ) ||
Smaller( first, second ) )
return false;
Returns true if the first integer is smaller then the second and false otherwise
HugeInteger.asmx.cs
Returns true if the two integers are equal and false otherwise

14. HugeInteger.asmx.cs Program Output
else
return true; }
238
} // end class HugeInteger
240
241 } // end namespace HugeIntegerWebService
HugeInteger.asmx.cs Program Output

15. 21.4 Publishing and Consuming Web Services
Fig Design view of a Web service.

16. 21.4 Publishing and Consuming Web Services
Fig Adding a Web service reference to a project.

17. 21.4 Publishing and Consuming Web Services
Link to root directory of web server
Fig Add Web Reference dialog.

18. 21.4 Publishing and Consuming Web Services
Fig Web services located on localhost.

19. 21.4 Publishing and Consuming Web Services
Fig Web reference selection and description.

20. 21.4 Publishing and Consuming Web Services
Service description
Web service discovery file
Proxy class
Fig Solution Explorer after adding a Web reference to a project.

21. UsingHugeIntegerService.cs 1 // Fig. 21.13: UsingHugeIntegerService.cs
2 // Using the HugeInteger Web Service. 3
4 using System;
5 using System.Drawing;
6 using System.Collections;
7 using System.ComponentModel;
8 using System.Windows.Forms;
9 using System.Web.Services.Protocols; 10
11 // allows user to perform operations on large integers
12 public class UsingHugeIntService : System.Windows.Forms.Form
13 {
private System.Windows.Forms.Label promptLabel;
private System.Windows.Forms.Label resultLabel; 16
private System.Windows.Forms.TextBox firstTextBox;
private System.Windows.Forms.TextBox secondTextBox; 19
private System.Windows.Forms.Button addButton;
private System.Windows.Forms.Button subtractButton;
private System.Windows.Forms.Button biggerButton;
private System.Windows.Forms.Button smallerButton;
private System.Windows.Forms.Button equalButton; 25
private System.ComponentModel.Container components = null; 27
// declare a reference Web service
private localhost.HugeInteger remoteInteger; 30
private char[] zeroes = { '0' }; 32
UsingHugeIntegerService.cs

22. Instantiate remoteInteger to be a new HugeInteger object
// default constructor
public UsingHugeIntService() {
InitializeComponent(); 37
// instantiate remoteInteger
remoteInteger = new localhost.HugeInteger(); } 41
// Visual Studio .NET generated code 43
[STAThread]
static void Main() {
Application.Run( new UsingHugeIntService() ); 48
} // end Main 50
// checks whether two numbers user input are equal
protected void equalButton_Click(
object sender, System.EventArgs e ) {
// make sure HugeIntegers do not exceed 100 digits
if ( CheckSize( firstTextBox, secondTextBox ) )
return; 58
// call Web-service method to determine
// whether integers are equal
if ( remoteInteger.EqualTo(
firstTextBox.Text, secondTextBox.Text ) ) 63
resultLabel.Text =
firstTextBox.Text.TrimStart( zeroes ) +
" is equal to " +
secondTextBox.Text.TrimStart( zeroes );
Instantiate remoteInteger to be a new HugeInteger object
UsingHugeIntegerService.cs
Call HugeInteger Web method EqualTo remotely

23. Call HugeInteger Web method Smaller remotely
else
resultLabel.Text =
firstTextBox.Text.TrimStart( zeroes ) +
" is NOT equal to " +
secondTextBox.Text.TrimStart( zeroes ); 73
} // end method equalButton_Click 75
// checks whether first integer input
// by user is smaller than second
protected void smallerButton_Click(
object sender, System.EventArgs e ) {
// make sure HugeIntegers do not exceed 100 digits
if ( CheckSize( firstTextBox, secondTextBox ) )
return; 84
// call Web-service method to determine whether first
// integer is smaller than second
if ( remoteInteger.Smaller(
firstTextBox.Text, secondTextBox.Text ) ) 89
resultLabel.Text =
firstTextBox.Text.TrimStart( zeroes ) +
" is smaller than " +
secondTextBox.Text.TrimStart( zeroes );
else
resultLabel.Text =
firstTextBox.Text.TrimStart( zeroes ) +
" is NOT smaller than " +
secondTextBox.Text.TrimStart( zeroes ); 99
} // end method smallerButton_Click
101
Call HugeInteger Web method Smaller remotely
UsingHugeIntegerService.cs

24. Call HugeInteger Web method Bigger remotely UsingHugeIntegerService.cs
// checks whether first integer input
// by user is bigger than second
protected void biggerButton_Click(
object sender, System.EventArgs e ) {
// make sure HugeIntegers do not exceed 100 digits
if ( CheckSize( firstTextBox, secondTextBox ) )
return;
110
// call Web-service method to determine whether first
// integer is larger than the second
if ( remoteInteger.Bigger( firstTextBox.Text,
secondTextBox.Text ) )
115
resultLabel.Text =
firstTextBox.Text.TrimStart( zeroes ) +
" is larger than " +
secondTextBox.Text.TrimStart( zeroes );
else
resultLabel.Text =
firstTextBox.Text.TrimStart( zeroes ) +
" is NOT larger than " +
secondTextBox.Text.TrimStart( zeroes );
125
} // end method biggerButton_Click
127
// subtract second integer from first
protected void subtractButton_Click(
object sender, System.EventArgs e ) {
// make sure HugeIntegers do not exceed 100 digits
if ( CheckSize( firstTextBox, secondTextBox ) )
return;
135
Call HugeInteger Web method Bigger remotely
UsingHugeIntegerService.cs

25. Call HugeInteger Web method Subtract remotely
// perform subtraction
try {
string result = remoteInteger.Subtract(
firstTextBox.Text,
secondTextBox.Text ).TrimStart( zeroes );
142
resultLabel.Text = ( ( result == "" ) ? "0" : result ); }
145
// if WebMethod throws an exception, then first
// argument was smaller than second
catch ( SoapException ) {
MessageBox.Show(
"First argument was smaller than the second" ); }
153
} // end method subtractButton_Click
155
// adds two integers input by user
protected void addButton_Click(
object sender, System.EventArgs e ) {
// make sure HugeInteger does not exceed 100 digits
// and is not situation where both integers are 100
// digits long--result in overflow
if ( firstTextBox.Text.Length > 100 ||
secondTextBox.Text.Length > 100 ||
( firstTextBox.Text.Length == 100 &&
secondTextBox.Text.Length == 100 ) ) {
UsingHugeIntegerService.cs
Call HugeInteger Web method Subtract remotely

26. Call HugeInteger Web method Add remotely UsingHugeIntegerService.cs
MessageBox.Show( "HugeIntegers must not be more "
"than 100 digits\nBoth integers cannot be of"
" length 100: this causes an overflow",
"Error", MessageBoxButtons.OK,
MessageBoxIcon.Information );
173
return; }
176
// perform addition
resultLabel.Text = remoteInteger.Add( firstTextBox.Text,
secondTextBox.Text ).TrimStart( zeroes ).ToString();
180
} // end method addButton_Click
182
// determines whether size of integers is too big
private bool CheckSize( TextBox first, TextBox second ) {
if ( first.Text.Length > 100 || second.Text.Length > 100 ) {
MessageBox.Show( "HugeIntegers must be less than 100"
" digits", "Error", MessageBoxButtons.OK,
MessageBoxIcon.Information );
191
return true; }
194
return false;
196
} // end method CheckSize
198
199 } // end class UsingHugeIntegerService
Call HugeInteger Web method Add remotely
UsingHugeIntegerService.cs

27. UsingHugeIntegerService.cs Program Output

28. 1 // Fig. 21.14: BlackjackService.asmx.cs
2 // Blackjack Web Service which manipulates a deck of cards. 3
4 using System;
5 using System.Collections;
6 using System.ComponentModel;
7 using System.Data;
8 using System.Diagnostics;
9 using System.Web;
10 using System.Web.Services; 11
12 namespace BlackjackWebService
13 {
[ WebService(
Namespace = "
Description = "A Web service that provides methods " +
"to manipulate a deck of cards." ) ]
public class BlackjackService : System.Web.Services.WebService { 20
// Visual Studio .NET generated code 22
// deal new card
[ WebMethod( EnableSession = true,
Description = "Deal a new card from the deck." ) ]
public string DealCard() {
string card = "2 2"; 29
BlackjackService.asmx.cs
Method DealCard with WebMethod attribute which allows client applications to invoke it
Property EnableSession is set to true allowing this method to maintain session information

29. Set card to be the first object in deck (cast to a string)
// get client's deck
ArrayList deck = ( ArrayList ) Session[ "deck" ];
card = ( string ) deck[ 0 ];
deck.RemoveAt( 0 );
return card; 35
} // end method DealCard 37
[ WebMethod( EnableSession = true,
Description = "Create and shuffle a deck of cards." ) ]
public void Shuffle() {
Random randomObject = new Random(); 43
ArrayList deck = new ArrayList(); 45
// generate all possible cards
for ( int i = 2; i < 15; i++ ) {
for ( int j = 0; j < 4; j++ ) {
deck.Add( i + " " + j ); } } 52
// swap each card with another card randomly
for ( int i = 0; i < deck.Count; i++ ) {
int newIndex = randomObject.Next( deck.Count );
object temporary = deck[ i ];
deck[ i ] = deck[ newIndex ];
deck[ newIndex ] = temporary; } 61
// add this deck to user's session state
Session[ "deck" ] = deck; }
Retrieve the deck variable from the Session object. Cast the resulting object to an ArrayList and assign local variable deck to reference it
Set card to be the first object in deck (cast to a string)
Generate all possible cards and add them to deck
BlackjackService.asmx.cs
Remove the first object from deck
Initialize deck to a new ArrayList object
Swap each card with a random card from the deck
Assign the Session variable deck to reference ArrayList deck

30. If the card is in Ace, increment aceCount but do not add to total65
// computes value of hand
[ WebMethod ( Description = "Compute a " +
"numerical value for the current hand." ) ]
public int CountCards( string dealt ) {
// split string containing cards
char[] tab = { '\t' };
string[] cards = dealt.Split( tab );
int total = 0, face, aceCount = 0; 75
foreach ( string drawn in cards ) {
// get face of card
face =
Int32.Parse( drawn.Substring(
, drawn.IndexOf( " " ) ) ); 82
switch ( face ) {
// if ace, increment number of aces in hand
case 14:
aceCount++;
break; 89
// if Jack, Queen or King, add 10 to total
case 11: case 12: case 13:
total += 10;
break; 94
BlackjackService.asmx.cs
If the card is in Ace, increment aceCount but do not add to total
Use method Split to create a string array containing the individual cards (stored in dealt and separated by tab characters)
Add 10 to total if the card is a Jack, Queen or King
Repeat loop for each member of cards

31. Otherwise, add the value of the card to total BlackjackService.asmx.cs
// otherwise, add value of face
default:
total += face;
break; 99
} // end switch
101
} // end foreach
103
// if any aces, calculate optimum total
if ( aceCount > 0 ) {
// if it is possible to count one ace as 11, and rest
// 1 each, do so; otherwise, count all aces as 1 each
if ( total aceCount - 1 <= 21 )
total += 11 + aceCount - 1;
else
total += aceCount; }
114
return total;
116
} // end method CountCards
118
} // end class BlackjackService
120
121 } // end namespace BlackjackWebService
Otherwise, add the value of the card to total
BlackjackService.asmx.cs
If it is possible to count one ace as 11, do so; otherwise, count each ace as 1

32. Blackjack.cs 1 // Fig. 21.15: Blackjack.cs
2 // Blackjack game that uses the Blackjack Web service. 3
4 using System;
5 using System.Drawing;
6 using System.Collections;
7 using System.ComponentModel;
8 using System.Windows.Forms;
9 using System.Data;
10 using System.Net; 11
12 // game that uses Blackjack Web Service
13 public class Blackjack : System.Windows.Forms.Form
14 {
private System.Windows.Forms.PictureBox pictureBox1;
private System.Windows.Forms.PictureBox pictureBox2;
private System.Windows.Forms.PictureBox pictureBox3;
private System.Windows.Forms.PictureBox pictureBox4;
private System.Windows.Forms.PictureBox pictureBox5;
private System.Windows.Forms.PictureBox pictureBox6;
private System.Windows.Forms.PictureBox pictureBox7;
private System.Windows.Forms.PictureBox pictureBox8;
private System.Windows.Forms.PictureBox pictureBox9;
private System.Windows.Forms.PictureBox pictureBox10;
private System.Windows.Forms.PictureBox pictureBox11;
private System.Windows.Forms.PictureBox pictureBox12;
private System.Windows.Forms.PictureBox pictureBox13;
private System.Windows.Forms.PictureBox pictureBox14;
private System.Windows.Forms.PictureBox pictureBox15;
private System.Windows.Forms.PictureBox pictureBox16;
private System.Windows.Forms.PictureBox pictureBox17;
private System.Windows.Forms.PictureBox pictureBox18;
private System.Windows.Forms.PictureBox pictureBox19;
private System.Windows.Forms.PictureBox pictureBox20;
private System.Windows.Forms.PictureBox pictureBox21;
Blackjack.cs

33. Instantiate a new BlackjackService object
private System.Windows.Forms.PictureBox pictureBox22; 37
private System.Windows.Forms.Button dealButton;
private System.Windows.Forms.Button hitButton;
private System.Windows.Forms.Button stayButton; 41
private System.ComponentModel.Container components = null; 43
private localhost.BlackjackService dealer;
private string dealersCards, playersCards;
private ArrayList cardBoxes;
private int playerCard, dealerCard; 48
// labels displaying game status, dealer and player
private System.Windows.Forms.Label dealerLabel;
private System.Windows.Forms.Label playerLabel;
private System.Windows.Forms.Label statusLabel; 53
public enum GameStatus :
int { PUSH, LOSE, WIN, BLACKJACK }; 56
public Blackjack() {
InitializeComponent(); 60
dealer = new localhost.BlackjackService(); 62
// allow session state
dealer.CookieContainer = new CookieContainer(); 65
cardBoxes = new ArrayList(); 67
// put PictureBoxes into cardBoxes
cardBoxes.Add( pictureBox1 );
cardBoxes.Add( pictureBox2 );
Blackjack.cs
Instantiate a new BlackjackService object
Instantiate dealer’s CookieContainer property to allow the Web service to maintain session state information

34. Blackjack.cs 71 cardBoxes.Add( pictureBox3 );91
} // end method Blackjack 93
// Visual Studio .NET generated code 95
[STAThread]
static void Main() {
Application.Run( new Blackjack() );
100
} // end Main
102
Blackjack.cs

35. If dealer went over 21, players wins
// deals cards to dealer while dealer's total is
// less than 17, then computes value of each hand
// and determines winner
protected void stayButton_Click(
object sender, System.EventArgs e ) {
stayButton.Enabled = false;
hitButton.Enabled = false;
dealButton.Enabled = true;
DealerPlay(); }
114
// process dealers turn
private void DealerPlay() {
// while value of dealer's hand is below 17,
// dealer must take cards
while ( dealer.CountCards( dealersCards ) < 17 ) {
dealersCards += "\t" + dealer.DealCard();
DisplayCard( dealerCard, "" );
dealerCard++;
MessageBox.Show( "Dealer takes a card" ); }
127
int dealersTotal = dealer.CountCards( dealersCards );
int playersTotal = dealer.CountCards( playersCards );
130
// if dealer busted, player wins
if ( dealersTotal > 21 ) {
GameOver( GameStatus.WIN );
return; }
137
Blackjack.cs
While the dealer’s hand totals less then 17, the dealer must take cards
If dealer went over 21, players wins
Call method DealerPlay to process the dealer’s turn when the user wishes to stay

36. Deal the player a card as requested
// if dealer and player have not exceeded 21,
// higher score wins; equal scores is a push.
if ( dealersTotal > playersTotal )
GameOver( GameStatus.LOSE );
else if ( playersTotal > dealersTotal )
GameOver( GameStatus.WIN );
else
GameOver( GameStatus.PUSH );
146
} // end method DealerPlay
148
// deal another card to player
protected void hitButton_Click(
object sender, System.EventArgs e ) {
// get player another card
string card = dealer.DealCard();
playersCards += "\t" + card;
DisplayCard( playerCard, card );
playerCard++;
158
int total = dealer.CountCards( playersCards );
160
// if player exceeds 21, house wins
if ( total > 21 )
GameOver( GameStatus.LOSE );
164
If neither the dealer nor the player have went over 21, higher score wins; equal scores result in a push
Blackjack.cs
Deal the player a card as requested
If player went over 21, the house wins

37. If the player has 21, the player cannot take more cards; dealer’s turn
// if player has 21, they cannot take more cards
// the dealer plays
if ( total == 21 ) {
hitButton.Enabled = false;
DealerPlay(); }
172
} // end method hitButton_Click
174
// deal two cards each to dealer and player
protected void dealButton_Click(
object sender, System.EventArgs e ) {
string card;
180
// clear card images
foreach ( PictureBox cardImage in cardBoxes )
cardImage.Image = null;
184
// clear status from previous game
statusLabel.Text = "";
187
// shuffle cards
dealer.Shuffle();
190
// deal two cards to player
playersCards = dealer.DealCard();
DisplayCard( 11, playersCards );
card = dealer.DealCard();
DisplayCard( 12, card );
playersCards += "\t" + card;
197
If the player has 21, the player cannot take more cards; dealer’s turn
Blackjack.cs
Clear the PictureBoxes containing the card images
Shuffle the cards by calling BlackjackService method Shuffle
Deal two cards to player

38. Deal two cards to dealer but only display the face of the first one
// deal two cards to dealer, only display face
// of first card
dealersCards = dealer.DealCard() ;
DisplayCard( 0, dealersCards );
card = dealer.DealCard();
DisplayCard( 1, "" );
dealersCards += "\t" + card;
205
stayButton.Enabled = true;
hitButton.Enabled = true;
dealButton.Enabled = false;
209
int dealersTotal = dealer.CountCards( dealersCards );
int playersTotal = dealer.CountCards( playersCards );
212
// if hands equal 21, it is a push
if ( dealersTotal == playersTotal &&
dealersTotal == 21 )
GameOver( GameStatus.PUSH );
217
// if player has 21 player wins with blackjack
else if ( playersTotal == 21 )
GameOver( GameStatus.BLACKJACK );
221
// if dealer has 21, dealer wins
else if ( dealersTotal == 21 )
GameOver( GameStatus.LOSE );
225
dealerCard = 2;
playerCard = 13;
228
} // end method dealButton_Click
230
Deal two cards to dealer but only display the face of the first one
Blackjack.cs
If only the dealer has 21, the dealer wins
If only the player has 21, the player wins
If both hands equal 21, it is a push

39. Retrieve face and suit of card from cardValue
// displays card represented by cardValue in
// PictureBox with number card
public void DisplayCard( int card, string cardValue ) {
// retrieve appropriate PictureBox from ArrayList
PictureBox displayBox = ( PictureBox ) cardBoxes[ card ];
237
// if string representing card is empty,
// set displayBox to display back of card
if ( cardValue == "" ) {
displayBox.Image =
Image.FromFile( "blackjack_images\\cardback.png" );
return; }
246
// retrieve face value of card from cardValue
int faceNumber = Int32.Parse( cardValue.Substring( 0,
cardValue.IndexOf( " " ) ) );
250
string face = faceNumber.ToString();
252
// retrieve the suit of the card from cardValue
string suit = cardValue.Substring(
cardValue.IndexOf( " " ) + 1 );
256
char suitLetter;
258
// determine if suit is other than clubs
switch ( Convert.ToInt32( suit ) ) {
// suit is clubs
case 0:
suitLetter = 'c';
break;
Blackjack.cs
Retrieve face and suit of card from cardValue
If cardValue is an empty string, display the back of the card image

40. Display all of dealer’s cards
266
// suit is diamonds
case 1:
suitLetter = 'd';
break;
271
// suit is hearts
case 2:
suitLetter = 'h';
break;
276
// else suit is spades
default:
suitLetter = 's';
break; }
282
// set displayBox to display appropriate image
displayBox.Image = Image.FromFile(
"blackjack_images\\" + face + suitLetter + ".png" );
286
} // end method DisplayCard
288
// displays all player cards and shows
// appropriate game status message
public void GameOver( GameStatus winner ) {
char[] tab = { '\t' };
string[] cards = dealersCards.Split( tab );
295
for ( int i = 0; i < cards.Length; i++ )
DisplayCard( i, cards[ i ] );
298
Blackjack.cs
Display all of dealer’s cards

41. Display appropriate message in statusLabel Blackjack.cs
// push
if ( winner == GameStatus.PUSH )
statusLabel.Text = "It's a tie!";
302
// player loses
else if ( winner == GameStatus.LOSE )
statusLabel.Text = "You Lose Try Again!";
306
// player wins
else if ( winner == GameStatus.WIN )
statusLabel.Text = "You Win!";
310
// player has won with blackjack
else
statusLabel.Text = "BlackJack!";
314
stayButton.Enabled = false;
hitButton.Enabled = false;
dealButton.Enabled = true;
318
} // end method GameOver
320
321 } // end class Blackjack
Display appropriate message in statusLabel
Blackjack.cs

42. Blackjack.cs Program Output

43. Blackjack.cs Program Output

44. Blackjack.cs Program Output

45. Reservation.asmx.cs 1 // Fig. 21.16: Reservation.asmx.cs
2 // Airline reservation Web Service. 3
4 using System;
5 using System.Data;
6 using System.Diagnostics;
7 using System.Web;
8 using System.Web.Services;
9 using System.Data.OleDb; 10
11 namespace AirlineReservation
12 {
// performs reservation of a seat
[ WebService( Namespace = "
Description = "Service that enables a user to " +
"reserve a seat on a plane." ) ]
public class Reservation : System.Web.Services.WebService {
private System.Data.OleDb.OleDbCommand
oleDbSelectCommand1;
private System.Data.OleDb.OleDbCommand
oleDbInsertCommand1;
private System.Data.OleDb.OleDbCommand
oleDbUpdateCommand1;
private System.Data.OleDb.OleDbCommand
oleDbDeleteCommand1;
private System.Data.OleDb.OleDbConnection
oleDbConnection1;
private System.Data.OleDb.OleDbDataAdapter
oleDbDataAdapter1; 31
// Visual Studio .NET generated code 33
Reservation.asmx.cs

46. Set a query to find seats of the specified criteria. Execute query.
// checks database to determine whether
// matching seat is available
[ WebMethod ( Description = "Method to reserve seat." ) ]
public bool Reserve( string seatType, string classType ) {
OleDbDataReader dataReader; 40
// try database connection
try {
// open database connection
oleDbConnection1.Open(); 46
// set and execute SQL query
oleDbDataAdapter1.SelectCommand.CommandText =
"SELECT Number FROM Seats WHERE Type = '" +
seatType + "' AND Class = '" + classType +
"' AND Taken = '0'" ;
dataReader =
oleDbDataAdapter1.SelectCommand.ExecuteReader(); 54
// if there were results, seat is available
if ( dataReader.Read() ) {
string seatNumber = dataReader.GetString( 0 ); 59
dataReader.Close(); 61
Reservation.asmx.cs
Set a query to find seats of the specified criteria. Execute query.
If Read method returned true, then query returned result(s)
Retrieve the first string in the row (the seat number)

47. 62 // update first available seat to be taken
oleDbDataAdapter1.UpdateCommand.CommandText =
"Update Seats Set Taken = '1' WHERE Number = '"
seatNumber + "'";
oleDbDataAdapter1.UpdateCommand.ExecuteNonQuery(); 67
return true; 69
} // end if
dataReader.Close(); }
catch ( OleDbException ) // if connection problem {
return false; }
finally {
oleDbConnection1.Close(); } 81
// no seat was reserved
return false; 84
} // end method Reserve 86
} // end class Reservation 88
89 } // end namespace AirlineReservation
Set a query that updates the seat numbered seatNumber to be taken. Execute query.
Reservation.asmx.cs

48. 21.6 Using Web Forms and Web Services
Fig Airline Web Service in design view.

49. 1 <%-- Fig. 21.18: TicketReservation.aspx --%>
2 <%-- A Web Form to allow users to select the kind of seat --%>
3 <%-- they wish to reserve %> 4
5 Page language="c#" Codebehind="TicketReservation.aspx.cs"
AutoEventWireup="false"
Inherits="MakeReservation.TicketReservation" %> 8
9 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
10 <HTML>
<HEAD>
<meta name="GENERATOR" Content="Microsoft Visual Studio 7.0">
<meta name="CODE_LANGUAGE" Content="C#">
<meta name="vs_defaultClientScript"
content="JavaScript (ECMAScript)">
<meta name="vs_targetSchema"
content="
</HEAD>
<body MS_POSITIONING="GridLayout"> 20
<form id="MakeReservation" method="post" runat="server"> 22
<asp:DropDownList id="seatList" style="Z-INDEX: 101;
LEFT: 16px; POSITION: absolute; TOP: 43px"
runat="server" Width="105px" Height="22px"> 26
<asp:ListItem Value="Aisle">Aisle</asp:ListItem>
<asp:ListItem Value="Middle">Middle</asp:ListItem>
<asp:ListItem Value="Window">Window</asp:ListItem> 30
</asp:DropDownList> 32
TicketReservation.aspx

50. 33 <asp:DropDownList id="classList" style="Z-INDEX: 102;
LEFT: 145px; POSITION: absolute; TOP: 43px"
runat="server" Width="98px" Height="22px"> 36
<asp:ListItem Value="Economy">Economy</asp:ListItem>
<asp:ListItem Value="First">First</asp:ListItem> 39
</asp:DropDownList> 41
<asp:Button id="reserveButton" style="Z-INDEX: 103;
LEFT: 21px; POSITION: absolute; TOP: 83px"
runat="server"Text="Reserve">
</asp:Button> 46
<asp:Label id="Label1" style="Z-INDEX: 104;
LEFT: 17px; POSITION: absolute; TOP: 13px"
runat="server">Please select the type of seat and
class you wish to reserve:
</asp:Label> 52
</form>
</body>
55 </HTML>
TicketReservation.aspx

51. TicketReservation.aspx.cs 1 // Fig. 21.19: TicketReservation.aspx.cs
2 // Making a Reservation using a Web Service. 3
4 using System;
5 using System.Collections;
6 using System.ComponentModel;
7 using System.Data;
8 using System.Drawing;
9 using System.Web;
10 using System.Web.SessionState;
11 using System.Web.UI;
12 using System.Web.UI.WebControls;
13 using System.Web.UI.HtmlControls; 14
15 namespace MakeReservation
16 {
// allows visitors to select seat type to reserve, and
// then make reservation
public class TicketReservation : System.Web.UI.Page {
protected System.Web.UI.WebControls.DropDownList
seatList;
protected System.Web.UI.WebControls.DropDownList
classList; 25
protected System.Web.UI.WebControls.Button
reserveButton;
protected System.Web.UI.WebControls.Label Label1; 29
private localhost.Reservation agent =
new localhost.Reservation(); 32
TicketReservation.aspx.cs

52. TicketReservation.aspx.cs 33 private void Page_Load(
object sender, System.EventArgs e ) {
if ( IsPostBack ) {
seatList.Visible = false;
classList.Visible = false;
reserveButton.Visible = false;
Label1.Visible = false; } } 44
// Visual Studio .NET generated code 46
// calls Web Service to try to reserve specified seat
public void reserveButton_Click (
object sender, System.EventArgs e ) {
// if Web-service method returned true, signal success
if ( agent.Reserve( seatList.SelectedItem.Text,
classList.SelectedItem.Text ) )
Response.Write( "Your reservation has been made."
" Thank you." ); 56
// Web-service method returned false, so signal failure
else
Response.Write( "This seat is not available, " +
"please hit the back button on your browser " +
"and try again." ); 62
} // end method reserveButton_Click 64
} // end class TicketReservation 66
67 } // end namespace MakeReservation
TicketReservation.aspx.cs

53. TicketReservation.aspx.cs Program Output

54. TicketReservation.aspx.cs Program Output

55. TemperatureServer.asmx.cs 1 // Fig. 21.20: TemperatureServer.asmx.cs
2 // TemperatureServer Web Service that extracts weather
3 // information from a Web page. 4
5 using System;
6 using System.Collections;
7 using System.ComponentModel;
8 using System.Data;
9 using System.Diagnostics;
10 using System.Web;
11 using System.Web.Services;
12 using System.IO;
13 using System.Net; 14
15 namespace TemperatureWebService
16 {
[ WebService( Namespace = "
Description = "A Web service that provides information " +
"from the National Weather Service." ) ]
public class TemperatureServer :
System.Web.Services.WebService {
// Visual Studio .NET generated code 24
[ WebMethod( EnableSession = true, Description =
"Method to read information from the weather service." ) ]
public void UpdateWeatherConditions() {
// create WebClient to get access to Web page
WebClient myClient = new WebClient();
ArrayList cityList = new ArrayList(); 32
TemperatureServer.asmx.cs

56. 33 // get StreamReader for response so we can read page
StreamReader input = new StreamReader(
myClient.OpenRead(
" +
"traveler.html" ) ); 38
string separator = "TAV12"; 40
// locate first horizontal line on Web page
while ( !input.ReadLine().StartsWith(
separator ) ) ; // do nothing 44
// day format and night format
string dayFormat =
"CITY WEA HI/LO WEA " +
"HI/LO";
string nightFormat =
"CITY WEA LO/HI WEA " +
"LO/HI";
string inputLine = ""; 53
// locate header that begins weather information do {
inputLine = input.ReadLine();
} while ( !inputLine.Equals( dayFormat ) &&
!inputLine.Equals( nightFormat ) ); 60
// get first city's data
inputLine = input.ReadLine(); 63
TemperatureServer.asmx.cs

57. TemperatureServer.asmx.cs 64 while ( inputLine.Length > 28 ) 65 {{
// create CityWeather object for city
CityWeather weather = new CityWeather(
inputLine.Substring( 0, 16 ),
inputLine.Substring( 16, 7 ),
inputLine.Substring( 23, 7 ) ); 71
// add to List
cityList.Add( weather ); 74
// get next city's data
inputLine = input.ReadLine(); } 78
// close connection to NWS server
input.Close(); 81
// add city list to user session
Session.Add( "cityList", cityList ); 84
} // end UpdateWeatherConditions 86
// gets all city names
[ WebMethod( EnableSession = true, Description =
"Method to retrieve a list of cities." ) ]
public string[] Cities() {
ArrayList cityList = ( ArrayList ) Session[ "cityList" ];
string[] cities= new string[ cityList.Count ]; 94
TemperatureServer.asmx.cs

58. TemperatureServer.asmx.cs 95 // retrieve names for cities
for ( int i = 0; i < cityList.Count; i++ ) {
CityWeather weather = ( CityWeather ) cityList[ i ]; 99
cities[ i ] = weather.CityName; }
102
return cities;
104
} // end method Cities
106
// gets all city descriptions
[ WebMethod( EnableSession = true, Description = "Method" +
" to retrieve weather descriptions for a " +
"list of cities." )]
public string[] Descriptions() {
ArrayList cityList = ( ArrayList ) Session[ "cityList" ];
string[] descriptions= new string[ cityList.Count ];
115
// retrieve weather descriptions for all cities
for ( int i = 0; i < cityList.Count; i++ ) {
CityWeather weather = ( CityWeather )cityList[ i ];
120
descriptions[ i ] = weather.Description; }
123
return descriptions;
125
} // end method Descriptions
127
TemperatureServer.asmx.cs

59. TemperatureServer.asmx.cs 128 // obtains each city temperature
[ WebMethod( EnableSession = true, Description = "Method " +
"to retrieve the temperature for a list of cities." ) ]
public string[] Temperatures() {
ArrayList cityList = ( ArrayList ) Session[ "cityList" ];
string[] temperatures= new string[ cityList.Count ];
135
// retrieve temperatures for all cities
for ( int i = 0; i < cityList.Count; i++ ) {
CityWeather weather = ( CityWeather )cityList[ i ];
temperatures[ i ] = weather.Temperature; }
142
return temperatures;
144
} // end method Temperatures
146
} // end class TemperatureServer
148
149 } // end namespace TemperatureWebService
TemperatureServer.asmx.cs

60. CityWeather.cs 1 // Fig. 21.21: CityWeather.cs
2 // Class representing the weather information for one city. 3
4 using System; 5
6 namespace TemperatureWebService
7 {
public class CityWeather {
private string cityName;
private string temperature;
private string description; 13
public CityWeather(
string city, string information, string degrees ) {
cityName = city;
description = information;
temperature = degrees; } 21
// city name
public string CityName {
get {
return cityName; } } 30
CityWeather.cs

61. CityWeather.cs 31 // city temperature 32 public string Temperature{
get {
return temperature; } } 39
// forecast description
public string Description {
get {
return description; } } 48
} // end class CityWeather
50 } // end namespace TemperatureWebService
CityWeather.cs

62. Client.cs 1 // Fig. 21.22: Client.cs
2 // Class that displays weather information that it receives
3 // from a Web service. 4
5 using System;
6 using System.Drawing;
7 using System.Collections;
8 using System.ComponentModel;
9 using System.Windows.Forms;
10 using System.Net; 11
12 namespace TemperatureClient
13 {
public class Client : System.Windows.Forms.Form {
private System.Windows.Forms.Label label1;
private System.Windows.Forms.Label label2;
private System.Windows.Forms.Label label3;
private System.Windows.Forms.Label label4;
private System.Windows.Forms.Label label5;
private System.Windows.Forms.Label label6;
private System.Windows.Forms.Label label7;
private System.Windows.Forms.Label label8;
private System.Windows.Forms.Label label9;
private System.Windows.Forms.Label label10;
private System.Windows.Forms.Label label11;
private System.Windows.Forms.Label label12;
private System.Windows.Forms.Label label13;
private System.Windows.Forms.Label label14;
private System.Windows.Forms.Label label15;
private System.Windows.Forms.Label label16;
private System.Windows.Forms.Label label17;
private System.Windows.Forms.Label label18;
private System.Windows.Forms.Label label19;
private System.Windows.Forms.Label label20;
Client.cs

63. Client.cs 36 private System.Windows.Forms.Label label21;52
private System.ComponentModel.Container components =
null; 55
public Client() {
InitializeComponent(); 59
localhost.TemperatureServer client =
new localhost.TemperatureServer();
client.CookieContainer = new CookieContainer();
client.UpdateWeatherConditions(); 64
string[] cities = client.Cities();
string[] descriptions = client.Descriptions();
string[] temperatures = client.Temperatures(); 68
label35.BackgroundImage = new Bitmap(
"images/header.png" );
Client.cs

64. Client.cs 71 label36.BackgroundImage = new Bitmap(
"images/header.png" ); 73
// create Hashtable and populate it with every label
Hashtable cityLabels = new Hashtable();
cityLabels.Add( 1, label1 );
cityLabels.Add( 2, label2 );
cityLabels.Add( 3, label3 );
cityLabels.Add( 4, label4 );
cityLabels.Add( 5, label5 );
cityLabels.Add( 6, label6 );
cityLabels.Add( 7, label7 );
cityLabels.Add( 8, label8 );
cityLabels.Add( 9, label9 );
cityLabels.Add( 10, label10 );
cityLabels.Add( 11, label11 );
cityLabels.Add( 12, label12 );
cityLabels.Add( 13, label13 );
cityLabels.Add( 14, label14 );
cityLabels.Add( 15, label15 );
cityLabels.Add( 16, label16 );
cityLabels.Add( 17, label17 );
cityLabels.Add( 18, label18 );
cityLabels.Add( 19, label19 );
cityLabels.Add( 20, label20 );
cityLabels.Add( 21, label21 );
cityLabels.Add( 22, label22 );
cityLabels.Add( 23, label23 );
cityLabels.Add( 24, label24 );
cityLabels.Add( 25, label25 );
cityLabels.Add( 26, label26 );
cityLabels.Add( 27, label27 );
cityLabels.Add( 28, label28 );
cityLabels.Add( 29, label29 );
cityLabels.Add( 30, label30 );
Client.cs

65. Client.cs 106 cityLabels.Add( 31, label31 );
110
// create Hashtable and populate with
// all weather conditions
Hashtable weather = new Hashtable();
weather.Add( "SUNNY", "sunny" );
weather.Add( "PTCLDY", "pcloudy" );
weather.Add( "CLOUDY", "mcloudy" );
weather.Add( "MOCLDY", "mcloudy" );
weather.Add( "TSTRMS", "rain" );
weather.Add( "RAIN", "rain" );
weather.Add( "SNOW", "snow" );
weather.Add( "VRYHOT", "vryhot" );
weather.Add( "FAIR", "fair" );
weather.Add( "RNSNOW", "rnsnow" );
weather.Add( "SHWRS", "showers" );
weather.Add( "WINDY", "windy" );
weather.Add( "NOINFO", "noinfo" );
weather.Add( "MISG", "noinfo" );
weather.Add( "DRZL", "rain" );
weather.Add( "HAZE", "noinfo" );
weather.Add( "SMOKE", "mcloudy" );
131
Bitmap background = new Bitmap( "images/back.png" );
Font font = new Font( "Courier New", 8,
FontStyle.Bold );
135
// for every city
for ( int i = 0; i < cities.Length; i++ ) {
// use Hashtable cityLabels to find the next Label
Label currentCity = ( Label )cityLabels[ i + 1 ];
Client.cs

66. Client.cs 141 142 // set current Label's image to image
// corresponding to the city's weather condition -
// find correct image name in Hashtable weather
currentCity.Image = new Bitmap( "images/" +
weather[ descriptions[ i ].Trim() ] + ".png" );
147
// set background image, font and forecolor
// of Label
currentCity.BackgroundImage = background;
currentCity.Font = font;
currentCity.ForeColor = Color.White;
153
// set label's text to city name
currentCity.Text = "\r\n" + cities[ i ] + " " +
temperatures[ i ]; }
158
} // end of constructor
160
// Visual Studio .NET generated code
162
[STAThread]
static void Main() {
Application.Run( new Client() ); }
168
} // end class Client
170
171 } // end namespace TemperatureClient
Client.cs

67. Client.cs Program Output

68. Equation.cs 1 // Fig. 21.23: Equation.cs
2 // Class Equation that contains
3 // information about an equation. 4
5 using System; 6
7 public class Equation
8 {
private int left, right, result;
private string operation; 11
// required default constructor
public Equation() : this( 0, 0, "+" ) { } 16
// constructor for class Equation
public Equation( int leftValue, int rightValue,
string operationType ) {
Left = leftValue;
Right = rightValue;
Operation = operationType; 24
switch ( operationType ) {
case "+":
Result = Left + Right;
break;
case "-":
Result = Left - Right;
break;
Equation.cs

69. Equation.cs 33 case "*": 34 Result = Left * Right; 35 break; 36 } 37 }} } 38
public override string ToString() {
return Left.ToString() + " " + Operation + " " +
Right.ToString() + " = " + Result.ToString(); } 44
// property returning string representing
// left-hand side
public string LeftHandSide {
get {
return Left.ToString() + " " + Operation + " " +
Right.ToString(); } 54
set { } } 59
// property returning string representing
// right-hand side
public string RightHandSide {
get {
return Result.ToString(); }
Equation.cs

70. 68
set { } } 73
// left operand get and set property
public int Left {
get {
return left; } 81
set {
left = value; } } 87
// right operand get and set property
public int Right {
get {
return right; } 95
set {
right = value; } }
101
Equation.cs

71. Equation.cs 102 // get and set property of result of applying
// operation to left and right operands
public int Result {
get {
return result; }
110
set {
result = value; } }
116
// get and set property for operation
public string Operation {
get {
return operation; }
124
set {
operation = value; } }
130
131 } // end class Equation
Equation.cs

72. Generator.asmx.cs 1 // Fig. 21.24: Generator.asmx.cs
2 // Web Service to generate random equations based on a
3 // specified operation and difficulty level. 4
5 using System;
6 using System.Collections;
7 using System.ComponentModel;
8 using System.Data;
9 using System.Diagnostics;
10 using System.Web;
11 using System.Web.Services; 12
13 namespace EquationGenerator
14 {
[ WebService( Namespace = "
Description = "A Web service that generates questions " +
"based on the specified mathematical operation and " +
"level of difficulty chosen." ) ]
public class Generator : System.Web.Services.WebService { 21
// Visual Studio .NET generated code 23
[ WebMethod ( Description =
"Method that generates a random equation." ) ]
public Equation GenerateEquation( string operation,
int level ) {
// find maximum and minimum number to be used
int maximum = ( int ) Math.Pow( 10, level ),
minimum = ( int ) Math.Pow( 10, level - 1 ); 32
Generator.asmx.cs

73. Generator.asmx.cs 33 Random random = new Random(); 34
// create equation consisting of two random numbers
// between minimum and maximum parameters
Equation equation = new Equation(
random.Next( minimum, maximum ),
random.Next( minimum, maximum ), operation ); 40
return equation; 42
} // end method GenerateEquation 44
} // end class Generator 46
47 } // end namespace EquationGenerator
Generator.asmx.cs

74. 21.8 User Defined Types in Web Services
Create a subtraction exercise
Make exercise of user skill level 2
Fig Returning an object from a Web-service method. (Part 1)

75. 21.8 User Defined Types in Web Services
Fig Returning an object from a Web-service method. (Part 2)

76. Tutor.cs 1 // Fig. 21.26: Tutor.cs 2 // Math tutor program. 3
4 using System;
5 using System.Drawing;
6 using System.Collections;
7 using System.ComponentModel;
8 using System.Windows.Forms; 9
10 namespace EquationGeneratorClient
11 {
public class Tutor : System.Windows.Forms.Form {
private System.Windows.Forms.Panel panel1;
private System.Windows.Forms.Panel panel2; 16
private System.Windows.Forms.Label questionLabel;
private System.Windows.Forms.TextBox answerTextBox;
private System.Windows.Forms.Button okButton;
private System.Windows.Forms.Button generateButton; 21
private System.Windows.Forms.RadioButton oneRadioButton;
private System.Windows.Forms.RadioButton twoRadioButton;
private System.Windows.Forms.RadioButton
threeRadioButton;
private System.Windows.Forms.RadioButton addRadioButton;
private System.Windows.Forms.RadioButton
subtractRadioButton;
private System.Windows.Forms.RadioButton
multiplyRadioButton; 31
private System.ComponentModel.Container components =
null;
private int level = 1; 35
Tutor.cs

77. Tutor.cs 36 private localhost.Equation equation;
private localhost.Generator generator =
new localhost.Generator();
private string operation = "+"; 40
// Visual Studio .NET generated code 42
[STAThread]
static void Main() {
Application.Run( new Tutor() ); } 48
// generates new equation on click event
protected void generateButton_Click( object sender,
System.EventArgs e ) {
// generate equation using current operation
// and level
equation = generator.GenerateEquation( operation,
level ); 57
// display left-hand side of equation
questionLabel.Text = equation.LeftHandSide; 60
okButton.Enabled = true;
answerTextBox.Enabled = true; 63
} // end method generateButton_Click 65
Tutor.cs

78. Tutor.cs 66 // check users answer
protected void okButton_Click( object sender,
System.EventArgs e ) {
// determine correct result from Equation
// object
int answer = equation.Result; 73
// get user's answer
int myAnswer = Int32.Parse( answerTextBox.Text ); 76
// test if user's answer is correct
if ( answer == myAnswer ) {
questionLabel.Text = "";
answerTextBox.Text = "";
okButton.Enabled = false;
MessageBox.Show( "Correct! Good job!" ); }
else
MessageBox.Show( "Incorrect. Try again." ); 87
} // end method okButton_Click 89
// set the selected operation
protected void operationRadioButtons_Click( object sender,
EventArgs e ) {
RadioButton item = ( RadioButton ) sender; 95
Tutor.cs

79. Tutor.cs 96 // set the operation to be the appropriate symbol
if ( item == addRadioButton )
operation = "+";
else if ( item == subtractRadioButton )
operation = "-";
else
operation = "*";
103
generateButton.Text = "Generate " + item.Text +
" Example";
106
} // end method operationRadioButtons_Click
108
// set the current level
protected void levelRadioButtons_Click( object sender,
EventArgs e ) {
if ( sender == oneRadioButton )
level = 1;
else if ( sender == twoRadioButton )
level = 2;
else
level = 3;
119
} // end method levelRadioButtons_Click
121
} // end class Tutor
123
124 } // end namespace EquationGeneratorClient
Tutor.cs

80. Tutor.cs Program Output

81. Tutor.cs Program Output