Object reference not set to an instance of an object

[kothaisaravan]

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

one.cs
value = UIHelperConfig.GetSelectedPaymentTypeCode("CreditCard");

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

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

[ChrisHunter]

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

[kothaisaravan]

Hi,
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.