We help IT Professionals succeed at work.

Cannot convert from 'string' to 'System.Collections.Generic.List<string>'

dba123
dba123 asked
on
2,201 Views
Last Modified: 2008-01-09
I can't figure out why it's complaining  I must be passing the generic list wrong or something

I have in my class this:

        static void Main(string[] args)
        {
            List<string> rightToCheck = null;
            rightToCheck.Add("Delete");

            UAuthorizationProvider provider = new UAuthorizationProvider();
            IPrincipal principal;

            provider.Authorize(principal, rightToCheck);
        }

cannot convert from 'string' to 'System.Collections.Generic.List<string>'

My Authorize method is declared like this:

        public bool Authorize(IPrincipal principal, List<string> rightsRequested)
        {
             ...
         }
Comment
Watch Question

Guy Hengel [angelIII / a3]Billing Engineer
CERTIFIED EXPERT
Most Valuable Expert 2014
Top Expert 2009

Commented:
on which line does the error occur?
Jai STech Arch

Commented:
try using the full qualifier...
System.Collections.Generic.List<string> rightToCheck = null;

public bool Authorize(IPrincipal principal, System.Collections.Generic.List<string>  rightsRequested)

Author

Commented:
provider.Authorize(principal, rightToCheck);

Author

Commented:
Ok, I actually set it to a value now but still same error:

            IPrincipal principal = new GenericPrincipal(new GenericIdentity("John"), new string[] { "Manager" });

Author

Commented:
wait, I think it is working now.  Duh.
Guy Hengel [angelIII / a3]Billing Engineer
CERTIFIED EXPERT
Most Valuable Expert 2014
Top Expert 2009

Commented:
>new string[] { "Manager" }
is NOT the same as Generic.List<string>
so your last try cannot work...


looking...

Author

Commented:
no, that's for the principal.  I'm expecting a principal which I gave it.  The generic list is for the second argument.  I'm talking about the first.

Author

Commented:
so in other words I just tried this with no luck still

    class VAuthorizationProviderTesting
    {
        static void Main(string[] args)
        {
            List<string> rightToCheck = null;
            rightToCheck.Add("Delete");

            VAuthorizationProvider provider = new VAuthorizationProvider();
            IPrincipal principal = new GenericPrincipal(new GenericIdentity("Don"), new string[] { "Manager" });

            provider.Authorize(principal, rightToCheck);
        }
    }
}
Commented:
Unlock this solution and get a sample of our free trial.
(No credit card required)
UNLOCK SOLUTION

Commented:
Kelmen is right. first initialize it
List<string> rightToCheck =new List<string>();
then you can add.

Gain unlimited access to on-demand training courses with an Experts Exchange subscription.

Get Access
Why Experts Exchange?

Experts Exchange always has the answer, or at the least points me in the correct direction! It is like having another employee that is extremely experienced.

Jim Murphy
Programmer at Smart IT Solutions

When asked, what has been your best career decision?

Deciding to stick with EE.

Mohamed Asif
Technical Department Head

Being involved with EE helped me to grow personally and professionally.

Carl Webster
CTP, Sr Infrastructure Consultant
Empower Your Career
Did You Know?

We've partnered with two important charities to provide clean water and computer science education to those who need it most. READ MORE

Ask ANY Question

Connect with Certified Experts to gain insight and support on specific technology challenges including:

  • Troubleshooting
  • Research
  • Professional Opinions
Unlock the solution to this question.
Thanks for using Experts Exchange.

Please provide your email to receive a sample view!

*This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

OR

Please enter a first name

Please enter a last name

8+ characters (letters, numbers, and a symbol)

By clicking, you agree to the Terms of Use and Privacy Policy.