Conditional compilation in C#

       Programmers need to
debug, which sometimes requires identification of points in your program
where a programmer would like to insert code that would help him/her to
debug his/her code efficiently. A simple example might be inserting a
Console.Writeline() call that prints out values or indicates completion
(successful or unsuccessful) of the executed part. However, these lines
can clutter up the code structure and also needs removal of the
debugging code for the release of the entire software.

            
This overhead is taken care of by specialized methods in C# that
help the programmer debug the code without the need to clean up his/her
debugging code for the release phase. These methods which are used for
debugging are called Conditional methods.
The compiler identifies these marked methods and never includes them in
the release build.

            
Well, that’s good enough. But, how do I make a method
conditional? .NET provides an attribute System.Diagnostics.ConditionalAttribute
(alias Conditional) to achieve this. Let’s
look at some code now.

  Defining the conditional
method

 public class MyTracer

{

    [Conditional(“DEBUG”)]

    public static
void LogThisMessage(string myMessage, int
severity)

    {

        //  Write message to screen
or a file or …

        Console.WriteLine(” DEBUG MESSAGE : “ + myMessage

+” SEVERITY LEVEL : “+severity);

    }

}

 

The Conditional attribute has been applied to the LogThisMessage() method with the DEBUG conditional compilation symbol. This signals the
compiler that the method should be ignored if the conditional symbol DEBUG is not specified.

 

Using the conditional method

 With the Solution
Configurations set to Debug mode if you execute the following
code, you would happily see the output window shown below.

 

public static void
Main(string[]
args)

{

    //  Some error occured in my
code

    //  Log the message

    MyTracer.LogThisMessage(“The error 1221 has occured.”,
5);

}

 

 

 

Now lets see what happens
to our conditional code in the Release mode. To enable Debug or Release
mode you have to look for the Solution Configurations selector in your
Visual Studio IDE which is shown below.

 

 

Change the mode to “Release” and you would see that the conditional code
now has disappeared.

 

 

 

We used the predefined DEBUG compilation symbol in our code. You can have
your own defined symbols and use them for conditional compilation. You
can define custom compilation symbols in Project Properties -> Build
tab -> General. Checkboxes have been provided to enable or disable
the DEBUG and TRACE
symbols.

 

 

 

.NET also provides two
classes that provide similar functionality:

• System.Diagnostics.Debug
• System.Diagnostics.Trace

 These classes
contain methods that can also be used for debugging if you do not need
more specific custom methods.