I copied an asp.net website to another computer, and tried to compile it. First I used Nuget package manager to load the Ajax Control Toolkit from codeplex. This got most of the ajax controls working, but a few basic ones (that often come even without the toolkit) did not compile. Nor did they show up in the toolbox that appears when you are viewing a form.
I think the problem is that certain built-in controls also exist in the toolkit, or maybe they don't and have to be loaded some other way.
One compile error I get is:
Warning Element 'ScriptManager' is not a known element. This can occur if there is a compilation error in the Web site, or the web.config file is missing.
The web.config has:
<add tagPrefix="ajaxToolkit" assembly="AjaxControlToolkit" namespace="AjaxControlToolkit"/>
And a page with the scriptmanager has:
<asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>
I do see that the prefix is different, but if I change the 'asp' to 'ajaxToolkit' I still get an error.