Compiler Error CS0077

The as operator must be used with a reference type or nullable type ('int' is a non-nullable value type).

The as operator was passed a value type. Because as can return null, it can only be passed a reference type or a nullable value type.

However, using pattern matching with the is operator, we can directly perform type checking and assignments in one step.

The following sample generates CS0077:

// CS0077.cs  
using System;  

struct S  
{  
}  
  
class M  
{  
   public static void Main()  
   {  
      object o;
      S s;  

      o = new S();
  
      s = o as S;    // CS0077, S is not a reference type

      // Use pattern matching instead of as
      if (o is S sValue)
      {
          s = sValue;
      } 
   }  
}