ADO.NET Cookbook

7.1. Binding Simple Data to Web Forms Controls

Problem

You need to bind a field of data to a server-side control.

Solution

Use the DataBind( ) method.

The Web Forms page sample code displays the company name for the CustomerID specified by assigning the method GetCompanyName( ), which is defined in the code-behind file, to the Text property of TextBox control companyNameTextBox. The code for the Web Forms page is shown in Example 7-1.

Example 7-1. File: ADOCookbookCS0701.aspx

<asp:TextBox id="companyNameTextBox" style="Z-INDEX: 103; LEFT: 136px;
    POSITION: absolute; TOP: 128px" runat="server" ReadOnly="True"
    Width="280px" Text="<%# GetCompanyName(customerIdTextBox.Text) %>">
</asp:TextBox>

The code-behind contains one event and one method:

Page.Load

Binds data from the source—in this case the GetCompanyName( ) method—to the companyNameTextBox server control.

GetCompanyName( )

This method retrieves and returns the company name for a specified customer ID.

The C# code for the code-behind is shown in Example 7-2.

Example 7-2. File: ADOCookbookCS0701.aspx.cs

// Namespaces, variables, and constants using System; using System.Configuration; using System.Data; using System.Data.SqlClient; // . . . private void Page_Load(object sender, System.EventArgs e) { companyNameTextBox.DataBind( ); } public String GetCompanyName(String customerId) { String companyName = "Not found."; if (customerIdTextBox.Text != "") { // Create a command to retrieve the company name for the // user-specified customer ID. String ...