protected

void Button1_PreRender(object sender, EventArgs e)

{

string doubleSubmitScript = String.Format(@”if (typeof(Page_ClientValidate) == ‘function’) {{

if (!Page_ClientValidate()) {{ return false; }}

}}

this.value = ‘Please wait…’;

this.disabled = true;

{0};”

, ClientScript.GetPostBackEventReference(BeginButton, String.Empty));

Button1.OnClientClick = doubleSubmitScript;

}