C# Error CS1900 – Warning level must be zero or greater

C# Error

CS1900 – Warning level must be zero or greater

Reason for the Error & Solution

Warning level must be in the range 0-4

The compiler option can only take one of five possible values (0, 1, 2, 3, or 4). Any other value passed to /warn will result in CS1900.

The following sample generates CS1900:

// CS1900.cs  
// compile with: /W:5  
// CS1900 expected  
class x  
{  
   public static void Main()  
   {  
   }  
}