Example of Pre-Selecting a Data-Driven Dropdown list box
Dropdown List Box
You can enter a category in the Textbox and then click on the Button labeled "Select Default Category ID" to set the default selection of the dropdown list box .
==== Source Code Listing ===
<%@ Page Language="VB" %>
<%@ import Namespace="System.Data.OleDb" %>
<%@ import Namespace="System.Data" %>
<script runat="server">
Sub Page_Load( ByVal sender As System.Object, ByVal e As System.EventArgs)
If Not ISPostBack Then
Dim conn As OleDbConnection
conn = New _
OleDbConnection("PROVIDER=Microsoft.Jet.OLEDB.4.0;" & _
"Data Source=" & Server.MapPath("Northwind.mdb") )Dim ds As DataSet = New DataSet()
Dim da As OleDbDataAdapter = New _
OleDbDataAdapter("select CategoryID, CategoryName from Categories ORDER BY CategoryName", conn)
da.Fill(ds, "Categories")
' Use a DataView as a DataSource
DropDownList1.DataSource = ds
DropDownList1.DataMember = "Categories"
DropDownList1.DataTextField = "CategoryName"
DropDownList1.DataValueField = "CategoryID"
Page.DataBind()
End If
End Sub
Sub ButtonSubmit_Click(sender As Object, e As EventArgs)
Label1.Text = "Category name selected is " + DropDownList1.SelectedItem.Text
Label1.Text &= "<br>Category ID selected is " + DropDownList1.SelectedItem.Value
End Sub
Sub ButtonSetCategoryID_Click(sender As Object, e As EventArgs)
DropDownList1.SelectedValue = TextBoxCID.Text
Label1.Text = "Default category name set is " + DropDownList1.SelectedItem.Text
Label1.Text &= "<br>Default category ID set is " + TextBoxCID.Text
End Sub
</script>
<html>
<head>
</head>
<body>
<form runat="server">
<p>
Category:
<asp:DropDownList id="DropDownList1" runat="server" Width="157px"></asp:DropDownList>
</p>
<p>
<asp:Button id="ButtonSubmit" onclick="ButtonSubmit_Click" runat="server" Text="Submit"></asp:Button>
</p>
<p>
Category ID Chosen:
<asp:TextBox id="TextBoxCID" runat="server"></asp:TextBox>
</p>
<p>
<asp:Button id="ButtonSetCategoryID" onclick="ButtonSetCategoryID_Click"
runat="server"
Text="Select Default Category ID"></asp:Button>
</p>
<p>
<asp:Label id="Label1" runat="server"></asp:Label>
</p>
<!-- Insert content here -->
</form>
</body>
</html>