I have a C# 2.0 application where a base interface allows read-only access to a value in a concrete class. But, within the concrete class, I'd like to have read/write access to that value. So, I have an implementation like this:

public abstract class Base
{
    public abstract DateTime StartTime { get; }
}

public class Foo : Base
{
    DateTime start_time_;

    public override DateTime StartTime
    {
        get { return start_time_; }
        internal set { start_time_ = value; }
    }
}

But, this gives me the error:

Foo.cs(200,22): error CS0546: 'Foo.StartTime.set': cannot override because 'Base.StartTime' does not have an overridable set accessor

I don't want the base class to have write access. But, I do want the concrete class to provide read/write access. Is there a way to make this work?

Thanks, PaulH

Unfortunately, Base can't be changed to an interface as it contains non-abstract functionality also. Something I should have thought to put in the original problem description.

public abstract class Base
{
    public abstract DateTime StartTime { get; }

    public void Buzz()
    {
        // do something interesting...
    }
}

My solution is to do this:

public class Foo : Base
{
    DateTime start_time_;

    public override DateTime StartTime
    {
        get { return start_time_; }
    }

    internal void SetStartTime
    {
        start_time_ = value;
    }
}

It's not as nice as I'd like, but it works.