How to use RowCommand Event of GridVIew using asp.net C#

*******RowCommand Event of GridView******************
protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e) 
{ 
if (e.CommandName == "Select") 
 {
 txtMobile.Text = Convert.ToString(e.CommandArgument); lblMessage.Text = "this the mobile no of selected row!"; 
  }
 }