C# 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).

Note: 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.