create a class file for message box
as example
message.cs in bll
public void ShowAlertMessage(string error)
{
Page page = HttpContext.Current.Handler as Page;
if (page != null)
{
error = error.Replace("'", "\'");
ScriptManager.RegisterStartupScript(page, page.GetType(), "err_msg", "alert('" + error + "');", true);
}
}
and place the code.
now you add your serverside
message msg = new message();
cmd.Parameters.Add("@Message", SqlDbType.VarChar, 500);
cmd.Parameters["@Message"].Direction = ParameterDirection.Output;
int result= cmd.ExecuteNonQuery();
if (result >= 1)
{
msg.Showalertmessage("Your Message!..");
}