User-1499637000 posted
Hi,
It should work, try setting to null or space.
Here is the example where
SqlDataSource1.FilterExpression = "";
Is working fine for me.
Example:
<%@ Page Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
protected void btnClearFilter_Click(object sender, EventArgs e)
{
SqlDataSource1.FilterExpression = "";
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>SQL DataSource Clear filter example</title>
</head>
<body>
<form id="form1" runat="server">
<div>
Choose Category :
<asp:DropDownList ID="ddCategories" runat="server" AutoPostBack="true" DataSourceID="SqlDataSource2"
DataTextField="CategoryID" DataValueField="CategoryID">
</asp:DropDownList>
<br />
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="ProductID"
DataSourceID="SqlDataSource1">
<Columns>
<asp:BoundField DataField="ProductID" HeaderText="ProductID" InsertVisible="False"
ReadOnly="True" SortExpression="ProductID" />
<asp:BoundField DataField="ProductName" HeaderText="ProductName" SortExpression="ProductName" />
<asp:BoundField DataField="CategoryID" HeaderText="CategoryID" SortExpression="CategoryID" />
</Columns>
</asp:GridView>
<br />
<asp:Button ID="btnClearFilter" runat="server" Text="ClearFilter"
onclick="btnClearFilter_Click" />
</div>
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"
SelectCommand="SELECT [ProductID], [ProductName], [CategoryID] FROM [Products]"
FilterExpression="CategoryId='{0}'">
<FilterParameters>
<asp:ControlParameter ControlID="ddCategories" PropertyName="SelectedValue" Name="CategoryId" />
</FilterParameters>
</asp:SqlDataSource>
<asp:SqlDataSource ID="SqlDataSource2" runat="server" ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"
SelectCommand="SELECT DISTINCT [CategoryID], [CategoryName] FROM [Categories] order by [CategoryID]">
</asp:SqlDataSource>
</form>
</body>
</html>
Hope the above example helps to solve your problem.
