I have installed AjaxControlToolkit package and added those .dll files, also added them to reference. The problem is when I use ComboBox in the code it is showing error
Could not find schema information for the element AjaxControlToolkit error;
Could not load file or assembly 'AjaxControlToolkit, Version=17.1.1.0, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)
how to fix this problem?