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This sample shows a non-code way to use a DropDownList for a search. It populates with the Categories table of the Northwind Database, so to use this code, as presented, you'll need to create a connectionString entry in your Web.Config called 'NorthwindConnectionString'. As you will see, by choosing a category in the DropDownlist, the Gridview is then populated using the selected item from the DropDownList.
All the controls you’ll need on the page are a DropDownList, a Gridview and 2 SQLDataSource controls.
<asp:DropDownListID="ddlCategories" runat="server" DataSourceID="dsCategories"
DataTextField="CategoryName"
DataValueField="CategoryID" AutoPostBack="True">
</asp:DropDownList>
<br />
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"
DataKeyNames="ProductID" DataSourceID="dsProducts">
<Columns>
<asp:BoundField DataField="ProductID" HeaderText="ProductID"
InsertVisible="False"
ReadOnly="True" SortExpression="ProductID" />
<asp:BoundField DataField="ProductName" HeaderText="ProductName"
SortExpression="ProductName" />
</Columns>
</asp:GridView>
<asp:SqlDataSource ID="dsCategories" runat="server"
ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"
SelectCommand="SELECT [CategoryID], [CategoryName] FROM [Categories] ORDER BY[CategoryName]">
</asp:SqlDataSource>
<asp:SqlDataSource ID="dsProducts" runat="server"
ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"
SelectCommand="SELECT [ProductID], [ProductName] FROM [Products] WHERE ([CategoryID] = @CategoryID) ORDER BY [ProductName]">
<SelectParameters>
<asp:ControlParameter ControlID="ddlCategories" Name="CategoryID"
PropertyName="SelectedValue" Type="Int32" />
</SelectParameters>
</asp:SqlDataSource> |