C# - Generic interfaces

Question

Where do generic interfaces are quite useful ? ( I am a beginner,so simple example will definitely helpful).

Answer 1

Its useful when you need an interface, but you also need to abstract the data type. Simple example

public interface IMyShape<T>
{
   T X { get; }
   T Y { get; }
}

public class IntSquare : IMyShape<int>
{
   int X { get { return 100; } }
   int Y { get { return 100; } }
}

public class IntTriangle : IMyShape<int>
{
   int X { get { return 200; } }
   int Y { get { return 200; } }
}

public class FloatSquare : IMyShape<float>
{
   float X { get { return 100.05; } }
   float Y { get { return 100.05; } }
}

Answer 2

你可以先看一下IEnumerable<T> 。

Answer 3

Generic interfaces are really useful when you want to parameterize the types of one of the members in the interface. Consider the IEnumerable and IEnumerable<T> interfaces. The first iterates Objects whereas the second iterates instances of the type argument supplied for T .

Since interfaces can be generic it allows you to leverage their flexibility while still taking advantage of generics in the same way that you would for a concrete type.