.net - C# Delegate as object -

disclaimer: unit-test related info question not relevant - can skip "the problem" if you're not familiar this, helps set context.

i have class need unit-test. looks this:

public class numberparser {     public static void checkbyterange(string str){...}     [...]     public static void checkfloatrange(string str){...}     [...] } 

i want use nunit parametrized unit-test test these methods. here's test method:

    [testcasesource("checkrange_overflow_inputs")]     public void checkrange_overflow(string value, action<string> method)     {         assert.throws<exception>(() => method(value));     } 

the test uses testcasesourceattribute specify field contains list of sets of arguments test method.

now, nunit expects field called checkrange_overflow_inputs, of type object[], contains object[] elements, each of contains values arguments test method.

the problem:

ideally, i'd write field this:

    private static readonly object[] checkrange_overflow_inputs         = new object[]               {                   new object[]{byte.maxvalue,  numberparser.checkbyterange },                   [...]                   new object[]{float.maxvalue, numberparser.checkfloatrange },                   [...]               }; 

but compiler complains can't cast method group object.

that makes sense - numberparser.checkbyterange ambiguous, e.g. overloaded.

but how can compiler allow me save (as object) the method called numberparser.checkbyterange takes string , returns void ?

what tried (and failed succeeded):

 [...]  new object[]{byte.maxvalue, (action<string>)numberparser.checkbyterange },  [...] 

if method static, attempt have worked. can't work as

(action<string>)numberparser.checkbyterange 

when checkbyterange instance (non-static) method because haven't told instance (this) use. either:

• make checkbyterange static method
• tell instance use, i.e. (action<string>)someinstance.checkbyterange

with them static, following compiles fine me:

private static readonly object[] checkrange_overflow_inputs     = new object[]           {               new object[]{byte.maxvalue,  (action<string>) numberparser.checkbyterange },               new object[]{float.maxvalue, (action<string>) numberparser.checkfloatrange },           };