Question

如何使vb Form使用Mutex成为单个实例。对于开发人员！

嗨，我在网上搜索了如何在VB Net中而不是在C＃代码中创建单实例启动表单。这是我的解决方案：

在项目中选择“添加课程...”
在“ NativeMethods.vb”中重命名新类，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

在项目中选择“添加课程...”
在“ main.vb”中重命名新类，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

在Form1上输入以下行：

    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

在项目中选择“属性项目名称...”
取消选中以下复选框：“启用应用程序框架”
在起始对象中选择：“ Sub Main”
保存项目，创建解决方案并启动它

此解决方案效果很好，并且已经在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，请发布它。谢谢和最好的问候。

Answer 1

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NET中使用Mutex的单个实例

1 个答案: