1. Carnegie Mellon University MSCF1 C#/.NET Basics 2 Some code is from “C# in a Nutshell” and “Programming C#”

2. Carnegie Mellon University MSCF2 This week Event Handling and delegates ASP.NET Web Forms ASP.NET Web Services

3. Carnegie Mellon University MSCF3 Event Handling Model Delegates listen for the events and call registered handlers Each component has a delegate for every event it can raise We register a method with the delegate and the delegate will call the method asynchronously

4. Carnegie Mellon University MSCF4 Delegates (1) A Button, for example, needs to notify some object when it is pushed We don’t want to hardwire (in the button) which object to call A delegate is a reference type used to encapsulate a method with particular parameter types

5. Carnegie Mellon University MSCF5 Delegate (2) using System; delegate String Foo(String x); // create a delegate class class Test { public static void Main() { Foo f = new Foo(ConvertToUpperCase); // create a delegate object String answer = f("abcd"); // call the method in the // object Console.WriteLine(answer); } public static String ConvertToUpperCase(String s) { return s.ToUpper(); }

6. Carnegie Mellon University MSCF6 Delegate (3) public class Form1 : System.Windows.Forms.Form { private System.Windows.Forms.Button multiplyButton; public void foo() { this.multiplyButton = new System.Windows.Forms.Button(); this.multiplyButton.Text = "Multiply"; this.multiplyButton.Click += new System.EventHandler(this.multiplyButton_Click); } private void multiplyButton_Click(object sender, System.EventArgs e) { textBox3.Clear(); string op1Str = op1.Text; string op2Str = op2.Text; : } Delegate reference Delegate Encapsulated method

7. Carnegie Mellon University MSCF7 Multicast Delegate using System; // From C# In A Nutshell delegate void MethodInvoker(); // define delegate class class Test { static void Main() { // create a Test object // and call its constructor new Test(); }

8. Carnegie Mellon University MSCF8 Test() { MethodInvoker m = null; m += new MethodInvoker(Foo); // overloaded += m += new MethodInvoker(Goo); // delegate holds m(); // pointers to two } // methods m MethodInvoker void Foo() void Goo()

9. Carnegie Mellon University MSCF9 void Foo() { Console.WriteLine("Foo"); } void Goo() { Console.WriteLine("Goo"); } Output: Foo Goo

10. Carnegie Mellon University MSCF10 ASP.NET Web Forms (1) Web Forms bring rapid appplication development to the web Similar technology is available on J2EE platforms (struts, Java Server Faces) Drag and drop development for the web tier – write event handlers as in Windows Forms User interacts with the sever via a standard browser

11. Carnegie Mellon University MSCF11 ASP.NET Web Forms (2) Web pages are dynamically generated Standard HTML is sent to the browser Notepad would work but Visual Studio makes life easy The user interface code is in an.aspx file The logic (C# code) is stored in a separate file (containing event handling code) Every.aspx file has this “code-behind” file

12. Carnegie Mellon University MSCF12 ASP.NET Web Forms (3) Postback events are handled on the server with an HTTP request. For example, the submit button is clicked. Non-postback events are not handled by the server immediately. For example, text is entered into a form or the mouse is moved. State is automatically added to an otherwise stateless protocol..NET maintains the user’s session.

13. Carnegie Mellon University MSCF13 Web Form Life Cycle Complicated series of activities similar to what is found in J2EE struts and JSF For this class let’s just say that a lot of pre- and post-processing goes on for each web request

14. Carnegie Mellon University MSCF14 Creating A Web Form(1) Prerequisites: IIS and Front Page Server Extensions (use Internet Service Manager and right click on the web site/All Tasks/Configure Server Extensions) Start/Microsoft Visual Studio.NET/ New Project/Visual C#/ASP.NET Web Application/BinomialTreeWebApp Generated code goes into c:\Inetpub\wwwroot\BinomialTreeWebApp

15. Carnegie Mellon University MSCF15 Creating A Web Form(2) Two files generated - The.aspx file holds the HTML - The aspx.cs file holds the C# To see the C# code right click the form and select view code Note that you can see the design view or the HTML view (tabs on bottom)

16. Carnegie Mellon University MSCF16 Web Form Step-by-step(1) (1) Start with a simple C# program – Divider.cs using System; public class Divider { public int divide(int a, int b) { return a / b; } public static void Main(String[] args) { Divider s = new Divider(); Console.WriteLine(s.divide(10,5)); }

17. Carnegie Mellon University MSCF17 Web Form Step-by-step(2) (2) Compile to a.dll csc –t:library Divider.cs (3)Run.NET New Project choose C# select.NET Web Application enter location: http://localhost/ADivider

18. Carnegie Mellon University MSCF18 Web Form Step-by-step(3) (4) Paint the screen in design mode (5) Right click to get to backing code (6) Add a reference to the.dll with Project/Add Reference (7) Use the class

19. Carnegie Mellon University MSCF19 Web Services “The internet is evolving from a collection of isolated web sites and applications into a general communication bus for distributed applications.” Pradeep Tapadiya, author of “.NET Programming”

20. Carnegie Mellon University MSCF20 ASP.NET Web Services(1) 0) Check if IIS is running by attempting to visit http://localhost http://localhost 1) If it's not running click Start/Settings/Control Panel/Add Remove Programs/ Add Remove Windows Components and enable IIS. 2) If.NET was installed after IIS reconfigure IIS by running aspnet_regiis.exe /i from a command prompt.

21. Carnegie Mellon University MSCF21 ASP.NET Web Services(2) (1) Start with a simple C# program – Divider.cs using System; public class Divider { public int divide(int a, int b) { return a / b; } public static void Main(String[] args) { Divider s = new Divider(); Console.WriteLine(s.divide(10,5)); }

22. Carnegie Mellon University MSCF22 ASP.NET Web Services(3) (2) Compile to a.dll csc –t:library Divider.cs (3)Run.NET New Project choose C# select ASP.NET Web Service enter location: http://localhost/ADividerWS

23. Carnegie Mellon University MSCF23 ASP.NET Web Services(4) (4) Add a reference to the.dll with Project/Add Reference (5) Edit the web service sample so that it provides the correct signature and calls the divide method (6) Get the WSDL document from a browser (7) Run wsdl, compile the result, and write a client