Question

I know how to write a web-service but until now I used them with always ready scripts. What I want to do this time is, have a web-service will return a string and I want to display this string in a part of webpage. That part may be inside an update panel or not. I know how to use jquery. So my question is how do I call a web-service every 5 seconds and update a part of webpage with the result of web-service. This update should not interrupt any part of the page and never cause post-back.

How can I do that?

asp.net 4.0 , c# 4.0

Answer 1

If your page is already using updatepanels then you could reuse the ms ajax libraries with no need for the jquery library at all.

javascript:

  function GetMyString() {
   // Call a static page method to get your string
   PageMethods.GetMyStringWebMethod(OnSucceeded, OnFailed);

}

 function OnSucceeded(result, userContext, methodName) {
    $get('yourDivContainer').innerHTML = '<b>' + result + '</b>';
   setTimeout("GetMyString()", 5000); 
    }


function OnFailed(error, userContext, methodName) { }

function pageLoad() {
      // On initial load and partial postbacks, 
   GetMyString();

}

Page Method in your code behind:

    [WebMethod]
    public static string GetMyStringWebMethod()
    {

        return "the string";
    }

aspx:

change asp:ScriptManager to have EnablePageMethods=”true”

If you’re happy using jquery then just replace the Pagemethods call with an jquery.Ajax call passing in the GetMyStringWebMethod.aspx as the url and handle the string inset in the ajax success event.