#warning (C# Reference)

#warning lets you generate a level one warning from a specific location in your code. For example:

#warning Deprecated code in this method.  

Remarks

A common use of #warning is in a conditional directive. It is also possible to generate a user-defined error with #error.

Example

// preprocessor_warning.cs  
// CS1030 expected  
#define DEBUG  
class MainClass   
{  
    static void Main()   
    {  
#if DEBUG  
#warning DEBUG is defined  
#endif  
    }  
}  

See Also

C# Reference
C# Programming Guide
C# Preprocessor Directives