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HomeHomeDNN Open Source...DNN Open Source...Provider and Extension ForumsProvider and Extension ForumsClientAPIClientAPIConversion from type string to integer errorConversion from type string to integer error
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4/5/2009 9:39 PM

I have been researching the ClientAPI and am seriously considering implementing it as a standard feature of all of my future projects. There's only one problem... I can't get it to work. I know I've got to be overlooking something really simple here.

The test project is a simple module.

Here is the ascx code: 

<%@ Control language="vb" Inherits="Modules.APIClientTest.View" CodeFile="View.ascx.vb" AutoEventWireup="false" Explicit="True" %>

<script type="text/javascript">
    function successFunc(result, ctx)
    received: ' + result + ' (' + + ')');
    function errorFunc(result, ctx)
    failed: ' + result + ' (' + + ')');

<asp:Button ID="mybutton" runat="server" Text="Button" />



And the vb code behind is:

Imports DotNetNuke
Imports System.Web.UI
Imports DotNetNuke.UI.Utilities

Namespace Modules.APIClientTest

        Partial Class View
        Inherits Entities.Modules.PortalModuleBase
        Implements IClientAPICallbackEventHandler

#Region "Event Handlers"

        Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
                    If ClientAPI.BrowserSupportsFunctionality(ClientAPI.ClientFunctionality.XMLHTTP) _
                    AndAlso ClientAPI.BrowserSupportsFunctionality(ClientAPI.ClientFunctionality.XML) Then
                        ClientAPI.RegisterClientReference(Me.Page, ClientAPI.ClientNamespaceReferences.dnn_xml)
                        ClientAPI.RegisterClientReference(Me.Page, ClientAPI.ClientNamespaceReferences.dnn_xmlhttp)
                    End If

                    mybutton.Attributes.Add("onclick", ClientAPI.GetCallbackEventReference(Page, "'test'", "successFunc", "this", "errorFunc"))

            Catch exc As Exception
                ProcessModuleLoadException(Me, exc)
            End Try
        End Sub

#End Region

        Public Function RaiseClientAPICallbackEvent(ByVal EVENT_ARGUMENT As String) As String Implements DotNetNuke.UI.Utilities.IClientAPICallbackEventHandler.RaiseClientAPICallbackEvent
            Return "HELLO: " & EVENT_ARGUMENT
        End Function
    End Class

End Namespace

 When I run this module on a page I always get the same result. - errFunc is triggered and the 'result' variable contains:

400 - Conversion from string "test" to type 'Integer' is not valid.

Firebug indicates that a successful post has occured and I see the two variables populated correctly in the post data. It appears that there is indeed a round trip happening and the invalid conversion is happening at the server. Any idea what could cause this or what I could do to trace it further?


New Post
4/6/2009 8:55 AM

I have a sample module you can compare here (I believe the forum editor stripped out portions of your code).  Also, you may like to investigate my new templates for you project (, which includes video tutorials.

New Post
4/6/2009 1:15 PM

Actually, I figured it out this morning. Here is what I found:

I was using the Client API Callback pdf as a guide, which demonstrates triggering the process from a button as follows:

mybutton.attributes.add("onclick", GetCallbackEventReference(Page, "'test'", "successFunc", "this", "errorFunc")

This would cause the error every time. I made the following change and everything worked fine:

mybutton.attributes.add("onclick", GetCallbackEventReference(Me, "'test'", "successFunc", "this", "errorFunc")

Notice the only change is in the 1st param of the GetCallbackEventReference method. Since I am working at the module level, Me is the appropriate reference, not the page that the module exists on. I knew it had to be something obvious and minor.

All works great now! Awsome work on the ClientAPI and thank you. This API is miles ahead of anything else out there and your documentation is a real jewel. I have learned more about AJAX, Client-side scripting and RPC in two days of reading your articles than I have with everything else I have found over the past 6 months or more.

HomeHomeDNN Open Source...DNN Open Source...Provider and Extension ForumsProvider and Extension ForumsClientAPIClientAPIConversion from type string to integer errorConversion from type string to integer error

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