How to call a Webservice function from masterpage

Question

I want to open a html page when user presses a function key.

Now the capturing of the function key works fine, but the logic to open the appropriate page is written in Code-Behind of master page.

I read on internet that if I want to call function in code behind then I have to create a web- service and call the webservice method from master page.

But for some reason this is not working.May be I am not calling the web service properly.

Can some body please help?

Many Thanks

  <cc1:ToolkitScriptManager ID="ScriptManager1" runat="server" ScriptMode="Release" EnableHistory="true" EnableSecureHistoryState="false"
                EnablePageMethods="true" CombineScripts="false">
            <Scripts>                   
                <asp:ScriptReference Path="~/ShowHelpPage.asmx"  />   

            </Scripts>

        </cc1:ToolkitScriptManager> 

document.onkeydown = function(event){

            if(window.event && window.event.keyCode == 113)
            {
                window.open("HelpFile/index.html");

            }
            else if(event.which == 113)
            {
                 window.open("HelpFile/index.html");
                 DisplayHelpFile();
            }
        }       

        function DisplayHelpFile()
        {
          var i =  PageMethods.DisplayHelpPage();// I think this is wrong
          alert(i);
        }   

Web Method

[WebService(Namespace = "http://tempuri.org/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [ToolboxItem(false)]   

     [System.Web.Script.Services.ScriptService]
    public class ShowHelpPage : System.Web.Services.WebService
    {

        [WebMethod]
        public string DisplayHelpPage()
        {
            return "Window.Html";            

        }
    }

Answer 1

"I read on internet that if I want to call function in code behind then I have to create a web- service and call the webservice method from master page"

I assume in the context you are refering to methods and not functions. Do you want to call a method when you master page loads? I would think that you dont need to create a Web Service for this? Unless you want the client to initiate the request through Async and you are using JavaScript and AJAX to make the request. What are you trying to achieve? It seems to me this can be achieved through just javascript. If you call a page through JavaScript it should load itself?

Below achieving what you want but using just javascript.

     function keyHandler(e)
     {
         ... key handling script
         if(myKey == 'F1')
         {   
             window.location.href = '...';              
         }
     }
     document.onkeypress = keyHandler;

If you need to call this Web Service and it needs to be initiated from the Client you could use JQuery to do this. Use the same approach with ShowHelpPage.asmx storing the processing and your rendering handled through JavaScript. This also to the best of my knowledge removes the dependency on ToolkitScriptManager.

function DisplayHelpFile()         
{   
     $.ajax({
              type: "POST",
              url: "ShowHelpPage.asmx/DisplayHelpPage",
              data: "{}",
              contentType: "application/json; charset=utf-8",
              dataType: "json",
              success:function(result)
              {
                  alert(result);
              }
         },
         error: ErrorMessage
      });
      function ErrorMessage(result)
      {
        alert(result.status + ' ' + result.statusText + ' ' + result.responseText);
      }    
}    

Answer 2

Your web method needs to be static.