PageMethods and UpdatePanel

Question

I have a page hierarchy as the following

I want to execute a PageMethod if I click the 'SAVE' button, so I coded like the following

On Button Click I called

OnClientClick="return btnSaveAS_Clicked()"

Called the following on PageLoad of the inner user control

private void RegisterJavaScript()
{
    StringBuilder jScript = new StringBuilder();
    jScript.Append("<script type='text/javascript'>");
    jScript.Append(@"function btnSaveAS_Clicked() {
        var txtConditionName = document.getElementById('" + txtConditionName.ClientID + @"').value;
        PageMethods.Combine('hello','world', OnSuccess);
        function onSuccess(result)
        {
            alert(result);
        }
    }");
    jScript.Append("</script>");

    Page.ClientScript.RegisterStartupScript(this.GetType(), "conditions_key", jScript.ToString());
}

Coded page method as

[WebMethod]
public static string Combine(string s1, string s2) {
  return s1 + "," + s2;
}

But it gives the following error...

Answer 1

You cannot define page methods in ascx pages. You have to define them in your web form. If you want to have a page method, defined in your user control, you'd have to define a forwarding page method in you aspx page like below (source):

in user control:

[WebMethod]
[ScriptMethod(UseHttpGet = true)]
public static string MyUserControlPageMethod()
{
    return "Hello from MyUserControlPageMethod";
}  

in aspx.cs page:

[WebMethod]
[ScriptMethod]
public static string ForwardingToUserControlMethod()
{
    return WebUserControl.MyUserControlMethod();
}  

and in aspx page:

 function CallUserControlPageMethod()
 {
     PageMethods.ForwardingToUserControlPageMethod(callbackFunction);           
 }  

Alternatively, you could use ASMX services and jquery ajax methods (jQuery.ajax, jQuery.get, jQuery.post) to call your methods asynchronously (sample).

Another option would be defining http handlers and call them via jQuery as well (tutorial).