In C#
you cannot define true global variables (in the sense that they don't belong to any class).
This being said, the simplest approach that I know to mimic this feature consists in using a static class
, as follows:
public static class Globals
{
public const Int32 BUFFER_SIZE = 512; // Unmodifiable
public static String FILE_NAME = "Output.txt"; // Modifiable
public static readonly String CODE_PREFIX = "US-"; // Unmodifiable
}
You can then retrieve the defined values anywhere in your code (provided it's part of the same namespace
):
String code = Globals.CODE_PREFIX + value.ToString();
In order to deal with different namespaces, you can either:
Globals
class without including it into a specific namespace
(so that it will be placed in the global application namespace);namespace
.A useful feature for this is using static
As others have said, you have to create a class for your globals:
public static class Globals {
public const float PI = 3.14;
}
But you can import it like this in order to no longer write the class name in front of its static properties:
using static Globals;
[...]
Console.WriteLine("Pi is " + PI);
There's no such thing as a global variable in C#. Period.
You can have static members if you want:
public static class MyStaticValues
{
public static bool MyStaticBool {get;set;}
}
First examine if you really need a global variable instead using it blatantly without consideration to your software architecture.
Let's assuming it passes the test. Depending on usage, Globals can be hard to debug with race conditions and many other "bad things", it's best to approach them from an angle where you're prepared to handle such bad things. So,
static
class (for manageability). The basic outline for such a class would be:
public class Globals
{
private static bool _expired;
public static bool Expired
{
get
{
// Reads are usually simple
return _expired;
}
set
{
// You can add logic here for race conditions,
// or other measurements
_expired = value;
}
}
// Perhaps extend this to have Read-Modify-Write static methods
// for data integrity during concurrency? Situational.
}
Usage from other classes (within same namespace)
// Read
bool areWeAlive = Globals.Expired;
// Write
// past deadline
Globals.Expired = true;
Source: Stackoverflow.com