NET中使用Mutex的单实例 [英] Single Instance using Mutex in NET

问题描述

如何让vb Form成为单实例使用Mutex.对于开发者！

How to make vb Form a single instance use Mutex. For the developers!

我在网上搜索如何在VB Net中而不是在c#代码中制作单实例启动表单.这是我的解决方案:

Hi, I searched in the net how to make a single instance startup form in VB Net not in c# code. Here is my solution:

1. 在项目中选择添加类..."
2. 重命名NativeMethods.vb"中的新类并输入以下代码:

添加此引用:Imports System.Runtime.InteropServices

    Public Const HWND_BROADCAST As Integer = &HFFFF
        Public Shared ReadOnly WM_SHOWME As Integer = RegisterWindowMessage("WM_SHOWME")
        <DllImport("user32")>
        Public Shared Function PostMessage(ByVal hwnd As IntPtr, ByVal msg As Integer, ByVal wparam As IntPtr, ByVal lparam As IntPtr) As Boolean
        End Function
        <DllImport("user32")>
        Public Shared Function RegisterWindowMessage(ByVal message As String) As Integer
End Function

1. 在项目中选择添加类..."
2. 重命名main.vb"中的新类并输入以下代码:

添加此引用:Imports System.Threading

Public Sub Main()
        Dim Mutex As Mutex = New Mutex(True, "{8F6F0AC4-B9A1-45fd-A8CF-72F04E6BDE8F}")
        If Mutex.WaitOne(TimeSpan.Zero, True) Then
            Application.EnableVisualStyles()
            Application.SetCompatibleTextRenderingDefault(False)
            Application.Run(New Form1())
            Mutex.ReleaseMutex()
        Else
            MessageBox.Show("Another instance of this Application is already running.", "Attention Requested", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
            NativeMethods.PostMessage(CType(NativeMethods.HWND_BROADCAST, IntPtr), NativeMethods.WM_SHOWME, IntPtr.Zero, IntPtr.Zero)
        End If
    End Sub

1. 在 Form1 上输入以下几行:

    Private Const SW_HIDE As Integer = 0
    Private Const SW_SHOWNORMAL As Integer = 1
    Private Const SW_SHOWMINIMIZED As Integer = 2
    Private Const SW_SHOWMAXIMIZED As Integer = 3
    Private Const SW_SHOWNOACTIVATE As Integer = 4
    Private Const SW_RESTORE As Integer = 9
    Private Const SW_SHOWDEFAULT As Integer = 10

    Protected Overrides Sub WndProc(ByRef m As Message)
            Const WM_SYSCOMMAND As Integer = &H112
            Const SC_RESTORE As Integer = &HF120
            Const SC_MINIMIZE As Integer = &HF020
            If m.Msg = NativeMethods.WM_SHOWME Then
                ShowMe()
            End If
            If m.Msg = WM_SYSCOMMAND AndAlso CInt(m.WParam) = SC_RESTORE Then
            End If
            If m.Msg = WM_SYSCOMMAND AndAlso CInt(m.WParam) = SC_MINIMIZE Then
            End If
            MyBase.WndProc(m)
        End Sub

    Private Sub ShowMe()
            If WindowState = FormWindowState.Minimized Then
                WindowState = FormWindowState.Normal
            End If
            Show()
            Dim top As Boolean = TopMost
            TopMost = True
            TopMost = top
            'Here you can call your own function. For example if your application uses the command line!
        End Sub

1. 在项目中选择属性项目名称..."
2. 取消勾选:启用应用程序框架"
3. 在起始对象中选择:Sub Main"
4. 保存项目，创建解决方案并启动它

此解决方案运行良好，并已在 Windows 7/8.1 和 10 32/64 位上进行了测试.如果有人找到更好的解决方案，请发布.感谢并致以最诚挚的问候.

This solution works very well and has been tested on Windows 7/8.1 and 10 32/64 Bit. If anyone finds a better solution, please post it. Thanks and Best Regards.

推荐答案

在WinForms项目属性中，为什么不直接勾选Make single instance application?

In the WinForms project properties, why not just check the Make single instance application?

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