Preface

Read an article on the official account. 《C# To solve PC The problem of more open end programs 》.

The author created The mutex Mutex Realized :

bool mutexCreated;
var mutex = new Mutex(true, "MyApp", out mutexCreated);
if (mutexCreated)
{
    Application.Run(new Form1());
}
else
{
    MessageBox.Show(" The program is already open ");
}

Actually ,VB.NET Of WinForm The program provides a simpler implementation ：

No code required , Just tick

Nowadays, few people use VB.NET 了 , Can you migrate the same functions to C# What about China? ？

principle

Compile one VB.NET Of WinForm Program , Decompile the source code , Find the entrance Main Method ：

This entry class MyApplication Inherited from WindowsFormsApplicationBase Base class , Of the base class actually executed Run Method .

and Run Method used internally IsSingleInstance attribute , Determine whether to enable Single instance application ：

and IsSingleInstance Property is assigned in the constructor of the entry class ：

public MyApplication()
    : base(AuthenticationMode.Windows)
{
    base.IsSingleInstance = true;
    base.EnableVisualStyles = true;
    base.SaveMySettingsOnExit = true;
    base.ShutdownStyle = ShutdownMode.AfterMainFormCloses;
}

Realization

I know the principle , We can transform C# The implementation of the ：

class Program :  WindowsFormsApplicationBase
{
    public Program()
    {
        IsSingleInstance = true;
    }

    protected override void OnCreateMainForm()
    {
        MainForm = new Form1();
    } 

    [STAThread]
    static void Main(string[] args)
    {
        new Program().Run(args);
    }
}

Need to quote NuGet package Microsoft.VisualBasic

Next , So let's verify that .

Our program can only be opened once , The first 2 This run will activate the running window .

Conclusion

today , We quote Microsoft.VisualBasic Solve the problem of too many programs ！

Want to know more about , Please pay attention to my official account ”My IO“