Installing the ASP.NET AJAX Control Toolkit (Visual Studio 2008)

" AjaxControlToolkit.tlb could not be loaded " so, do it on right way :)

The AjaxControlToolkit is not a COM library, it is a regular .NET Assembly. From the toolbox, click "Add items", then on the ".NET Framework Components" tab click browse in the lower right. Select the control toolkit and you should be good to go.

1. Download and Install Microsoft Visual Studio 2008 Service Pack 1
This download installs Visual Studio 2008 Service Pack 1 (SP1) and the .NET Framework 3.5 SP1.

2. Download and Extract AjaxControlToolkit-Framework3.5SP1.zip

3. Make sure the SampleWebSite folder (folder in extracted file) is in a reasonably permanent location on your hard drive.

4. Open Visual Studio 2008 (sp1): You need to create a new Toolbox tab for the controls. Right-click the Toolbox and choose Add Tab. Then, enter a name (like AJAX Toolkit) and hit Enter.

5. You need to add the controls to the new tab. Right-click the blank tab you’ve
created and select Choose Items.

6. In .NET Framework Components click Browse. Find the AjaxControlToolkit.dll
(which is in the SampleWebSite\Bin folder) and click OK.

7. You'll get "Accordion" and "Accordion Pane" checked. Click ok.

The End :)