Do you think generic properties would be useful in .NET?

Question

I'm not talking about generic classes that declare properties or fields with the type of a generic parameter. I'm talking about generic properties which could be applied to both generic and non-generic classes.

I'm not talking about this:

public class Base<T>
{
    public T BaseProperty { get; set; }
}

I'm talking about this:

public class Base
{
    public T BaseProperty<T>
    {
       get
       {
          // Insert magic
       }
       set
       {
          // Insert magic
       }
    }
}

Or this:

public class Base<U>
{
    public T BaseProperty<T>
    {
       get
       {
          // Insert magic
       }
       set
       {
          // Insert magic
       }
    }

    public U OtherBaseProperty { get; set; }
}

The usage would go something like this:

var b = new Base();
b.BaseProperty<int> = 42;
int i = b.BaseProperty<int>;
b.BaseProperty<string> = "Hi";
string s = b.BaseProperty<string>;

Or for the second example:

var b = new Base<string>();
b.BaseProperty<int> = 42;
int i = b.BaseProperty<int>;
b.OtherBaseProperty = "Hi";
string s = b.OtherBaseProperty;

The // Insert Magic refers to handling each call to the generic property getter or setter that has a different type for the type parameter.

For example this:

b.BaseProperty<int> = 42;

Needs to be handled differently to:

b.BaseProperty<string> = "Hi";

I would envisage that for each type T if the getter is called before the setter is called then default(T) is returned. When the setter is called the value is stored per type T so that when the getter is subsequently called the previous value that was set for that type is returned.

Note that under the covers properties are just methods.

Do you think this would be useful?

Answer 1

I've had a couple of times where I would have liked the ability to do this, yes.

However, the syntax involved would be pretty ugly, and it's sufficiently rarely useful that I think I prefer to just suck it up and go with generic methods.

Answer 2

No .