Hi all,

I got the error in design window "Object reference not set to an instance of an object."
Instances of this error occurs at two cs files

value = UIHelperConfig.GetSelectedPaymentTypeCode("CreditCard");

public static string GetSelectedPaymentTypeCode(string paymentType)
            return ConfigurationManager.AppSettings.GetValues(paymentType)[0];

How to make my design window viewable??
Any help??

make sure you have instantiated, assigned all you instances correctly and have all the correct DLL's at the top of your .cs files (example below).

Using UIHelper; 

hope this helps

I have included all using statement at the top of my cs file.
Even other design windows does not cause any problem. Only one design window is not viewable.