Conditional. In C#, a Conditional method is not always executed. It is compiled into the program only when certain symbols are defined with #define.
The Conditional attribute enables conditional compilation. It accepts a string argument—this is the symbol that must be defined for the method to be compiled.
And This is because variables can be assigned to method return values. You can work around this limitation using parameters.
#define PERLS#undef DOT
using System;
using System.Diagnostics;
class Program
{
static void Main()
{
MethodA();
MethodB();
}
[Conditional("PERLS")]
static void MethodA()
{
Console.WriteLine(true);
}
[Conditional("DOT")]
static void MethodB()
{
Console.WriteLine(false);
}
}True
Conditional List. It is possible to modify a collection in DEBUG mode. You can add strings or other values conditionally—when debugging your application, not when it's deployed.
Info The program defines an AddToArray method, which simply adds two elements to the array. It uses the Conditional("DEBUG") attribute.
Detail This means to only compile the method if DEBUG is defined. The Conditional attribute requires System.Diagnostics.
using System;
using System.Collections.Generic;
using System.Diagnostics;
class Program
{
static void Main()
{
List<string> l = new List<string>();
l.Add("rabbit");
l.Add("bird");
AddToArray(l);
Console.WriteLine("Elements: {0}", l.Count);
}
[Conditional("DEBUG")]
static void AddToArray(List<string> l)
{
// New array
string[] a = new string[2];
a[0] = "cat";
a[1] = "mouse";
// Add array to end of list
l.AddRange(a);
}
}Elements: 4Elements: 2
You can encapsulate your DEBUG-specific logic in separate Conditional("DEBUG") methods. This improves code clarity and performance, and reduces complexity.
Summary. Conditional allows us to create a method whose existence depends on a preprocessor directive. The Conditional attribute fits with the clear syntax of the C# language.
Dot Net Perls is a collection of tested code examples. Pages are continually updated to stay current, with code correctness a top priority.
Sam Allen is passionate about computer languages. In the past, his work has been recommended by Apple and Microsoft and he has studied computers at a selective university in the United States.
This page was last updated on Jan 25, 2022 (edit).
