1. Using List Controls with SQL Server
Working with Data-Bound DropDownLists, RadioButtons, and CheckBoxes

2. List Web Controls You’ve worked with DropDownList controls
Similar to the Visual Basic ComboBox
ASP provides two new controls:
RadioButtonList – a series of radio buttons
CheckBoxList – a series of check boxes
These controls share similar properties
An Items collection can be accessed in code
Can generate a SelectedIndexChanged event
Can optionally generate automatic postback
Items collection can be set up thru VS, your code, or populated by a data source control

3. Binding to a List Web Control
Binding process uses a Text and Value property similar to a ComboBox control
Create a new web page ListControls.aspx
Add an SqlDataSource named SqlDsCategory
Sql Select access only – no Insert, Update, Delete
Select all rows & all columns from Categories table
Add DropDown, CheckBox, & RadioButton lists
Configure the list controls
Choose SqlDsCategory as the data source
Choose Description to display and Code as Value
Web page shows book category types
Value property returns category code (key)

4. Filtering with a DropDownList
Remove RadioButtonList and CheckBoxList
Add a 2nd SqlDataSource
Select ISBN, Title, Author, YearPublished, and Price columns from the Books table
Add a Where clause
Set Column to CategoryCode
Source to Control
Control ID to the DropDownList control
Add a GridView using the new SqlDataSource
Select the new data source for the GridView
View the resulting web page

5. Filtering and AutoPostBack
First category automatically selected
Web page shows 1 Book in this category
Change Category selected in drop down list
No change in books listed
Must set AutoPostBack true for drop down list
Change drop down list AutoPostBack to true
View web page again
GridView automatically filters for book category

6. Filtering with a RadioButtonList
Remove DropDownList, add RadioButtonList
Set RadioButtonList AutoPostBack true
Change Where clause for grid SqlDataSource
Remove previous Where clause
Set Column to CategoryCode
Source to Control
Control ID to the RadioButtonList control
Resulting web page shows no books initially
Click on a radio button
GridView automatically filters for book category
Note that CheckBoxList won’t work in this case

7. Formatting a RadioButtonList
RadioButtonList shown in one long column
Preferable to have several shorter columns
Use RepeatColumns property to do this
Set RepeatColumns to 4
Increase CellPadding to 10 to provide spacing
RepeatDirection determines whether the first items appear in the first column or first row

8. Selecting Multiple Categories
Use CheckBoxList to select multiple categories
But this exceeds the abilities of Visual Studio
Need a variable number of Where clauses
SqlDataSource does not allow for this
Time to write some code!

9. Sql Server Connection String
Sql Server connection string in web.config:
Web site folder located at B:\WEB250
Books.mdf residing in App_Data folder
"Data Source=(LocalDB)\v11.0;
AttachDbFilename=B:\WEB250\ListControls\App_Data\Books.mdf;
Integrated Security=True;User Instance=False;"
Hard coding web site path usually a bad idea
Substitute |DataDirectory| for hard coded path
AttachDbFilename=|DataDirectory|\Books.mdf;

10. Using Web.Config Connect String
Test database access w/new ConnectionString
Remove SqlDataSource controls from page
Change data source for CheckBoxList and GridView controls to None
Connection strings are accessed in code as a property of the ConfigurationManager
conString =
ConfigurationManager.ConnectionStrings(“StringName").
ConnectionString
Web.config can hold many connection strings
StringName must match your connection string

11. Using Web.Config Connect String
Helpful to import namespaces to VB code
Imports System.Data
Imports System.Data.SqlClient
Eliminates need to preface classes with namespaces
Connection strings are accessed in code as a property of the ConfigurationManager
conString =
ConfigurationManager.ConnectionStrings(“StringName").
ConnectionString

12. Populating the CheckBoxList
sqlString = "Select CategoryCode, CategoryDescription from Categories;"
Dim dbConnObj As New SqlConnection(conString)
Dim cmdObj As New SqlCommand(sqlString, dbConnObj)
Dim adapterObj As SqlDataAdapter = New SqlDataAdapter
Dim tableObj As New DataTable
adapterObj.SelectCommand = cmdObj
adapterObj.Fill(tableObj)
With chklCategory
.DataSource = tableObj
.DataTextField = "CategoryDescription"
.DataValueField = "CategoryCode"
.DataBind()
End With

13. CheckBoxList Properties
Each check box is an item in the CheckBoxList Items Collection
Number of check boxes chklCategory.Items.Count
If check box has been checked chklCategory.Items(i).Selected
Check box description displayed to user chklCategory.Items(i).Text
Check box value returned to program chklCategory.Items(i).Value.ToString

14. Populating the GridView
Drag a GridView to your web page
Do not select a data source for the GridView
Edit Columns to set up GridView columns
Add a BoundField for each column
Set properties for each BoundField
DataField must match database column
HeaderText displayed to user in column header
Build an SQL Where clause dynamically based on which check boxes have been selected
Retrieve Books table just like Category table
Ignore DataTextField and DataValueField which have no meaning for a GridView