Can't Access My Extension Method

Question

Looking for a way to check if an string contains in another ignoring upper/lower case, I found it:

Works fine. Then, I tried put it to my StringExtensions namespace.

namespace StringExtensions
{

    public static class StringExtensionsClass
    {
        //... 

        public static bool Contains(this string target, string toCheck, StringComparison comp)
        {
            return target.IndexOf(toCheck, comp) >= 0;
        }
    }
}

and then:

using StringExtensions;

...

if (".. a".Contains("A", StringComparison.OrdinalIgnoreCase))

but I get the following error:

No overload for method 'Contains' takes '2' arguments

How do I fix it?

Louis Kottmann · Answer 1 · 2011-12-27T14:14:48.427

26

When you want to use your extension, add this using statement:

using StringExtensions;

Because of the way Extension methods are declared, visual studio won't find them by itself, and the regular Contains method takes one argument, hence your exception.

edited Dec 27 '11 at 14:14

answered Dec 01 '11 at 17:28

Louis Kottmann

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Yup -- Intellisense will only _appear_ to work because the method name already exists. – Austin Salonen Dec 01 '11 at 17:30

score 6 · Accepted Answer · answered Dec 01 '11 at 17:54

6

I found my mistake:

for this works with dynamic type need use a cast to string. .ToString() method is not sufficient.

if (((string)result.body).Contains(foo, StringComparison.OrdinalIgnoreCase))

Works fine now. Thanks again stackoverflow. :)

answered Dec 01 '11 at 17:54

Jack

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4

Right, because it's `dynamic` there's no guarantee that it doesn't have a method called `ToString` that returns something other than a string, so the result of any method call on a `dynamic` is always treated as `dynamic` by the compiler – Davy8 Dec 01 '11 at 18:00

Can't Access My Extension Method

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