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

Unfortunately not - properties cannot be extended as such. However, you can just hide the property by using new:

interface IInherited : IBase
{
    // The new is actually unnecessary (you get warnings though), hiding is automatic
    new string Property1 { get; set; }
}

Or, you can make your own getter and setter methods which can be overriden (good 'ol Java style):

interface IBase
{
    string GetProperty1();
}
interface IInherited : IBase
{
    void SetProperty1(string str);
}

Properties are actually converted to getter and setter methods by the compiler.