<% @Import Namespace="System.Data" %>
<% @Import Namespace="System.Data.SqlClient" %>
<script language="vb" runat="server">
Sub Page_Load(sender as Object, e as EventArgs)
If Not Page.IsPostBack then
BindData()
End If
End Sub
Sub BindData()
'1. Create a connection
Dim myConnection as New SqlConnection(ConfigurationSettings.AppSettings("connectionString"))
'2. Create the command object, passing in the SQL string
Const strSQL as String = "SELECT PublisherID, Name FROM tblPublishers ORDER BY Name"
Dim myCommand as New SqlCommand(strSQL, myConnection)
myConnection.Open()
radlstPubs.DataSource = myCommand.ExecuteReader(CommandBehavior.CloseConnection)
radlstPubs.DataBind()
End Sub
Sub btnViewBooks_Click(sender as Object, e as EventArgs)
'If the user has not selected an item from the radiobuttonlist,
'do nothing
If radlstPubs.SelectedItem Is Nothing then Exit Sub
'1. Create a connection
Dim myConnection as New SqlConnection(ConfigurationSettings.AppSettings("connectionString"))
'2. Create the command object, passing in the SQL string
Dim strSQL as String = "SELECT Title, Description FROM tblBooks " & _
" WHERE PublisherID = " & radlstPubs.SelectedItem.Value & _
" ORDER BY Title"
Dim myCommand as New SqlCommand(strSQL, myConnection)
myConnection.Open()
dgBooks.DataSource = myCommand.ExecuteReader(CommandBehavior.CloseConnection)
dgBooks.DataBind()
lblTitle.Text = "Books Published by " & radlstPubs.SelectedItem.Text
End Sub
</script>
<html>
<body>
<h1>Radio Button List Demo</h1>
This demo illustrates how to use data-binding to dynamically
create a radio button list based on database information.
The data below is from the
<a href="http://www.4guysfromrolla.com/webtech/chapters/">Sample Chapters Database</a>.
First, the radio button list is bound to the <code>tblPublishers</code> table. Then,
when you select a publisher, a DataGrid Web control is populated with
the books provided by the selected publisher. (Adding paging to the DataGrid would be
a snap. Just read: <a href="http://www.4guysfromrolla.com/webtech/072101-1.shtml">Paing
Database Results in ASP.NET</a>!)
<p><hr><p>
<form runat="server">
<b>Choose a Publisher's Books to View</b><br>
<asp:radiobuttonlist id="radlstPubs" runat="server" Font-Name="Verdana"
DataValueField="PublisherID" DataTextField="Name" />
<br>
<asp:button id="btnViewBooks" runat="server" Font-Name="Verdana"
Text="View Published Books" OnClick="btnViewBooks_Click" />
<p align="center">
<asp:label id="lblTitle" runat="server" Font-Name="Verdana"
Font-Size="Large" Font-Bold="True" />
<asp:datagrid id="dgBooks" runat="server"
Font-Name="Verdana" Font-Size="Smaller"
HeaderStyle-BackColor="Purple" HeaderStyle-ForeColor="White"
HeaderStyle-Font-Size="Small" HeaderStyle-Font-Bold="True"
AutoGenerateColumns="False">
<Columns>
<asp:BoundColumn HeaderText="Book Title" HeaderStyle-HorizontalAlign="Center"
DataField="Title" />
<asp:BoundColumn HeaderText="Synopsis" HeaderStyle-HorizontalAlign="Center"
DataField="Description" />
</Columns>
</asp:datagrid>
</p>
</form> <
