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Archive for August, 2008:
Enums in C# - use sbyte
C# Code Specification:
The following example declares an enum type named Alignment with an underlying type of sbyte.
enum Alignment: sbyte
{
Left = -1,
Center = 0,
Right = 1
}
When you use enumerations in C# - you easy can declare new values as sbyte. Standart type of variable is int, but you can use and sbyte type.
C# - start only one copy of the program
If you need that the program was started an only to one copy - can take advantage of such simple and useful class:
public class SingleInstance
{
private bool firstInstance = false;
public bool FirstInstance
{
get { return firstInstance; }
}
public SingleInstance()
{
Mutex mutex=null;
try
{
mutex = Mutex.OpenExisting("ProgramName");
}
catch (WaitHandleCannotBeOpenedException e)
{
firstInstance = true;
}
if (mutex == null)
{
mutex = new Mutex(false, "ProgramName");
GC.KeepAlive(mutex);
}
}
}
Now, we need edit Program.cs like here:
[STAThread]
static void Main()
{
SingleInstance single = new SingleInstance();
if (single.FirstInstance)
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new MainForm());
}
}
Now the program will be started only in one copy. A code works on the different versions of Windows - including Vista.