Is Nested Interface allowed in C#

Nested Interfaces in C# means to define an interface inside another interface in C#. In C#, you cannot define an interface inside another interface directly. C# does not support nested interfaces like it supports nested classes. Interface definitions in C# are typically declared at the namespace level and cannot be nested within other interfaces.

However, you can have an interface that inherits from another interface. This is a form of extending an interface to include additional members while maintaining the existing members from the parent interface.

public interface IBaseInterface
{
    void SomeMethod();
}

public interface IDerivedInterface : IBaseInterface
{
    void AnotherMethod();
}

In this example, IDerivedInterface extends IBaseInterface and includes its members (SomeMethod) as well as additional members (AnotherMethod).

If you need to group related interfaces, you can place them within the same namespace or create a common base interface that is implemented by multiple interfaces to achieve the desired behavior.