C# Error CS0681 – The modifier ‘abstract’ is not valid on fields. Try using a property instead.

C# Error

CS0681 – The modifier ‘abstract’ is not valid on fields. Try using a property instead.

Reason for the Error & Solution

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 1

The following sample generates CS0681:

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

Example 2

Try the following code instead:

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