Using Pre-Compiler Directives in C# to toggle Debug Functionality

Question

I am attempting to use Pre-compiler directives to toggle certain features in my application. I am using Pre-compiler directives as opposed to const static variables because these features will not occur in the release version of the application.

Is it true that C# does not allow for all C Pre-compiler commands, ie, #if X > Y & etc.? My below code is throwing compiler errors. Is it possible to use Pre-compiler directives to toggle functionality in my application?

My solution is a very 'C++/C' way of achieving this functionality. What is the C# way of achieving this functionality?

#define DEBUG                   1 // Not allowed to assign values to constants?
#define USE_ALTERNATE_METHOD    0

public class MyApplication
{
    public MyApplication()
    {
        #if DBEUG > 0 // Not allowed these kinds of directives?
            RegressionTests.Run();
        #endif // DEBUG > 0
    }

    public void myMethod
    {
        #if USE_ALTERNATE_METHOD > 0
            // Do alternate stuff
        #else 
            // Do regular stuff
        #endif // USE_ALTERNATE_METHOD > 0
    }
}

Answer 1

Specifying just #if DEBUG does the work.

You cannot use pre-processor definitives like #define DEBUG 1 .

However you can just specify #define DEBUG or #define CustomDefinition and use it with the Conditional attribute.

Eg,

You can just do this:

#if DEBUG
Console.WriteLine("This will work in DEBUG mode alone");
#endif

Or you can specify conditional-attributes on top of the method that you wanna execute only in the debug mode.

Eg,

[Conditional("DEBUG")]
void ExecuteOnlyInDebugMode()
{
     // do stuff you wanna do.
}

For your example it has to be like this:

#define DEBUG                  
#define USE_ALTERNATE_METHOD       
public class MyApplication
{
    public MyApplication()
    {
        #if DEBUG
            RegressionTests.Run();
        #endif 
    }

    public void myMethod
    {
        #if USE_ALTERNATE_METHOD 
            // Do alternate stuff
            //do not execute the following. just return.
        #endif
            // Do regular stuff

    }
}

You can find more info here . Beautifully explained.

Also, read more that Conditional attribute, here.