Attributes - Illustrated C# 2005 - page 500

Compilation symbol
↓
[Conditional( "DoTrace" )]
static void TraceMessage(string str)
{
Console.WriteLine(str);
}

Example of Conditional Attribute
The following code shows a full example using of the Conditional attribute.

￿Method Main contains two calls to method TraceMessage .

￿ The declaration for method TraceMessage is adorned with the Conditional attribute,

which has the compilation symbol DoTrace as its parameter. So if DoTrace is defined, the
compiler will include the code for all the calls to TraceMessage .

Since the first line of code defines a compilation symbol named DoTrace , the compiler
will include the code for both calls to TraceMessage .

￿

#define DoTrace
using System;
using System.Diagnostics;

namespace AttributesConditional
{
class Program
{
[Conditional( "DoTrace" )]
static void TraceMessage(string str)
{
Console.WriteLine(str);
}

static void Main(string[] args)
{
TraceMessage("Start of Main");
Console.WriteLine("Doing work in Main.");
TraceMessage("End of Main");
}
}
}