What is it called when trying to overload a function based purely on the return type?

What is it called when trying to overload a function based purely on the return type?

ie:

Public String DoWork()

Public int DoWork()

You cannot do the above, right?

Is that called covar开发者_运维技巧iance?

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It's still called a "method overload" but sometimes you'll hear the more verbose "return-type method overload." It is not possible in C#.

From the C# specification:

The signature of a method must be unique in the class in which the method is declared. The signature of a method consists of the name of the method, the number of type parameters and the number, modifiers, and types of its parameters. The signature of a method does not include the return type.

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No, covariance refers to changing the return type when overriding not overloading.

From wikipedia

 class A {
 }

 class B extends A {
 }

 // Classes demonstrating method overriding:

 class C {
     A getFoo() {
         return new A();
     }
 }

 class D extends C {
     B getFoo() {
         return new B();
     }
 }

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The alternative is to use generics:

public T DoWork<T>()
{
}

Edited to fix grammar; the return type doesn't get enclosed in angle brackets.

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Return type is not included in method's signature. That is why you cannot have two methods that differ only by return type.

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You need to use an intermediate type to get this behaviour. Here's a way to do it in C++. I don't know so much C# but I believe it should support this technique.