 <p>I think you should use one <code>SqlDataSource</code> and change its <code>SelectCommnad</code> according to the selection of <code>dropdown</code>.</p> <pre><code>if(dropdwon.SelectedValue == "0"){ SqlDataSource1.SelectCommnad = "Your sp to search city"; GridView1.DataSourceID = SqlDataSource1; GridView1.DataBind(); } else if(dropdwon.SelectedValue == "1"){ SqlDataSource1.SelectCommnad = "Your sp to search country"; GridView1.DataSourceID = SqlDataSource1; GridView1.DataBind(); } </code></pre>