Compiler Error CS0681

The modifier 'abstract' is not valid on fields. Try using a property instead

You cannot make a field abstract. You can, however, have an abstract property that accesses the field.

Example

The following sample generates CS0681:

// CS0681.cs
// compile with: /target:library
abstract class C
{
    abstract int num;  // CS0681
}

Try the following code instead:

// CS0681b.cs
// compile with: /target:library
abstract class C
{
    public abstract int num
    {
       get;
       set;
    }
}