How to implement single instance per machine application?

Question

I have to restrict my .net 4 WPF application so that it can be run only once per machine. Note that I said per machine, not per session.
I implemented single instance ap

Answer 1

See below for full example of how a single instace app is done in WPF 3.5

public class SingleInstanceApplicationWrapper :
Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase
{
public SingleInstanceApplicationWrapper()
{
// Enable single-instance mode.
this.IsSingleInstance = true;
}
// Create the WPF application class.
private WpfApp app;
protected override bool OnStartup(
Microsoft.VisualBasic.ApplicationServices.StartupEventArgs e)
{
app = new WpfApp();
app.Run();
return false;
}
// Direct multiple instances.
protected override void OnStartupNextInstance(
Microsoft.VisualBasic.ApplicationServices.StartupNextInstanceEventArgs e)
{
if (e.CommandLine.Count > 0)
{
app.ShowDocument(e.CommandLine[0]);
}
}
}

Second part:

public class WpfApp : System.Windows.Application
{
protected override void OnStartup(System.Windows.StartupEventArgs e)
{
base.OnStartup(e);
WpfApp.current = this;
// Load the main window.
DocumentList list = new DocumentList();
this.MainWindow = list;
list.Show();
// Load the document that was specified as an argument.
if (e.Args.Length > 0) ShowDocument(e.Args[0]);
}
public void ShowDocument(string filename)
{
try
{
Document doc = new Document();
doc.LoadFile(filename);
doc.Owner = this.MainWindow;
doc.Show();
// If the application is already loaded, it may not be visible.
// This attempts to give focus to the new window.
doc.Activate();
}
catch
{
MessageBox.Show("Could not load document.");
}
}
}

Third part:

 public class Startup
    {
    [STAThread]
    public static void Main(string[] args)
    {
    SingleInstanceApplicationWrapper wrapper =
    new SingleInstanceApplicationWrapper();
    wrapper.Run(args);
    }
    }

You may need to add soem references and add some using statements but it shoudl work.

You can also download a VS example complete solution by downloading the source code of the book from here.

Taken From "Pro WPF in C#3 2008 , Apress , Matthew MacDonald" , buy the book is gold. I did.