Could not load file or assembly 'AjaxControlToolkit' or one of its dependencies

Programming, error messages and sample code > ASP.NET
It misses the AjaxControlToolkit.dll in the bin directory after you deploy the site.

1. Get AjaxControlToolkit via
2. Add AjaxControlToolkit.dll to your Reference folder(Right Click on Reference Folder  > Add Reference > browse  AjaxControlToolkit.dll).
3. Set Copy Local to True
4. Publish your site.