Interface inheritance: is extending properties possible?

Question

I want to do this:

interface IBase
{
    string Property1 { get; }
}

interface IInherited : IBase
{
    string Property1 { get; set; }
}

So th

Answer 1

Not explicitly, no. You have two options:

public interface IBase
{
    string Property1 { get; }
}

public interface IInherited : IBase
{
    void SetProperty1(string value);
}

Or you can just kill the compiler warning with the new keyword:

public interface IBase
{
    string Property1 { get; }
}

public interface IInherited : IBase
{
    new string Property1 { get; set; }
}

Unless you implement IInherited.Property1 explicitly, IBase will bind to your settable implementation automatically.