单击代码中的消息框

Question

好吧，不要问为什么，请，但我真的需要这个。

因此，我会向用户显示一个MessageBox 2秒钟，然后我需要自动关闭它，而无需用户输入。

Messagebox.Show("RandomStringHere")
System.Threading.Thread.Sleep("2000")

在这里我被困住了。有什么办法可以做到吗？请不要问为什么，但确实有必要。

我无法在互联网上找到任何有关此问题的帮助，所以我猜你们可以帮助我。

Answer 1

只需创建自己的表单。您可以在设计器中执行此操作，也可以使用下面示例中的代码。设置计时器并在两秒钟内关闭表单：

Private _msgForm As Form
Private _tmr As Windows.Forms.Timer

Private Sub Button9_Click(sender As Object, e As EventArgs) Handles Button9.Click

    _msgForm = New Form
    With _msgForm
        .Height = 200
        .Width = 300
        .StartPosition = FormStartPosition.CenterScreen
        .Text = "Message"
    End With

    Dim btn As New Button
    With btn
        .Text = "OK"
        .Top = _msgForm.Height - 75
        .Left = _msgForm.Width - 100
        .Anchor = AnchorStyles.Right Or AnchorStyles.Bottom
    End With
    _msgForm.Controls.Add(btn)

    Dim lbl As New Label
    With lbl
        .Text = "This is the text of the message box"
        .Left = 0
        .Top = 0
        .Width = _msgForm.ClientSize.Width
        .Height = _msgForm.ClientSize.Height - 120
        .Anchor = AnchorStyles.Bottom Or AnchorStyles.Left Or AnchorStyles.Right Or AnchorStyles.Top
    End With
    _msgForm.Controls.Add(lbl)

    _tmr = New Windows.Forms.Timer
    With _tmr
        .Interval = 2000
        .Enabled = True
    End With

    AddHandler _tmr.Tick, AddressOf TimerTick
    AddHandler btn.Click, AddressOf ButtonClick
    _msgForm.ShowDialog()

End Sub

Private Sub TimerTick(sender As Object, e As EventArgs)
    _msgForm.Close()
End Sub

Private Sub ButtonClick(sender As Object, e As EventArgs)
    CType(sender, Button).FindForm.Close()
End Sub

Answer 2

使用示例：

    Using New CenteredMessageBox(Owner:=Me,
                                 TextFont:=Me.Font,
                                 TimeOut:=2500)

        MessageBox.Show("Test Text", 
                        "Test Title", 
                        MessageBoxButtons.OK, 
                        MessageBoxIcon.Information)

    End Using

自定义消息框：

' [ Centered MessageBox ]
' By Elektro
'
' The author of the original idea is Hans Passant: 
' http://stackoverflow.com/questions/2576156/winforms-how-can-i-make-messagebox-appear-centered-on-mainform
'
' Examples :
'
'Using New CenteredMessageBox(Owner:=Me,
'                             TextFont:=New Font("Lucida Console", Font.SizeInPoints, FontStyle.Bold),
'                             TimeOut:=2500)
'
'    MessageBox.Show("Test Text", "Test Title", MessageBoxButtons.OK, MessageBoxIcon.Information)
'
'End Using

#Region " Centered MessageBox Class"

#Region " Imports "

Imports System.Drawing
Imports System.Runtime.InteropServices
Imports System.Text
Imports System.Windows.Forms

#End Region

Class CenteredMessageBox : Implements IDisposable

#Region " Variables, Objects, Properties "

    Private mTries As Integer = 0
    Private mOwner As Form
    Private mFont As Font
    Private mTimeOut As Integer
    Private WithEvents TimeoutTimer As Timer

    Private ReadOnly Property MessageBoxWindowHandle As IntPtr
        Get
            Return _MessageBoxWindowHandle
        End Get
    End Property
    Dim _MessageBoxWindowHandle As IntPtr = IntPtr.Zero


#End Region

#Region " P/Invoke "

    Friend Class NativeMethods

        Friend Const WM_SETFONT As Integer = &H30
        Friend Const WM_GETFONT As Integer = &H31

        Friend Delegate Function EnumThreadWndProc(hWnd As IntPtr, lp As IntPtr) As Boolean

        Friend Declare Function SetWindowPos Lib "user32" (ByVal hwnd As IntPtr, ByVal hWndInsertAfter As IntPtr, ByVal x As Integer, ByVal y As Integer, ByVal cx As Integer, ByVal cy As Integer, ByVal wFlags As UInt32) As Boolean

        <DllImport("user32.dll")>
        Friend Shared Function EnumThreadWindows(tid As Integer, callback As NativeMethods.EnumThreadWndProc, lp As IntPtr) As Boolean
        End Function

        <DllImport("kernel32.dll")>
        Friend Shared Function GetCurrentThreadId() As Integer
        End Function

        <DllImport("user32.dll", CharSet:=CharSet.Unicode)>
        Friend Shared Function GetClassName(hWnd As IntPtr, buffer As StringBuilder, buflen As Integer) As Integer
        End Function

        <DllImport("user32.dll")>
        Friend Shared Function GetDlgItem(hWnd As IntPtr, item As Integer) As IntPtr
        End Function

        <DllImport("user32.dll")>
        Friend Shared Function SendMessage(hWnd As IntPtr, msg As Integer, wp As IntPtr, lp As IntPtr) As IntPtr
        End Function

        <DllImport("user32.dll")>
        Friend Shared Function GetWindowRect(hWnd As IntPtr, ByRef rc As RECT) As Boolean
        End Function

        <DllImport("user32.dll")>
        Friend Shared Function MoveWindow(hWnd As IntPtr, x As Integer, y As Integer, w As Integer, h As Integer, repaint As Boolean) As Boolean
        End Function

        ''' <summary>
        ''' <para>The DestroyWindow function destroys the specified window. The function sends WM_DESTROY and WM_NCDESTROY messages to the window to deactivate it and remove the keyboard focus from it. The function also destroys the window's menu, flushes the thread message queue, destroys timers, removes clipboard ownership, and breaks the clipboard viewer chain (if the window is at the top of the viewer chain).</para>
        ''' <para>If the specified window is a parent or owner window, DestroyWindow automatically destroys the associated child or owned windows when it destroys the parent or owner window. The function first destroys child or owned windows, and then it destroys the parent or owner window.</para>
        ''' <para>DestroyWindow also destroys modeless dialog boxes created by the CreateDialog function.</para>
        ''' </summary>
        ''' <param name="hwnd">Handle to the window to be destroyed.</param>
        ''' <returns>If the function succeeds, the return value is nonzero. If the function fails, the return value is zero. To get extended error information, call GetLastError.</returns>
        <DllImport("user32.dll", CharSet:=CharSet.Unicode, SetLastError:=True)>
        Friend Shared Function DestroyWindow(hwnd As IntPtr) As <MarshalAs(UnmanagedType.Bool)> Boolean
        End Function

    End Class

    Structure RECT
        Public Left As Integer
        Public Top As Integer
        Public Right As Integer
        Public Bottom As Integer
    End Structure

#End Region

#Region " Constructors "

    ''' <summary>
    ''' Initializes a new instance of the <see cref="CenteredMessageBox"/> class.
    ''' </summary>
    ''' <param name="Owner">Indicates the form that owns this messagebox.</param>
    ''' <param name="TextFont">Indicates the text-font used to display the text label.</param>
    ''' <param name="TimeOut">
    ''' Indicates the timeout, in ms, to auto-close this <see cref="CenteredMessageBox"/>
    ''' Default is '0' which means Infinite.
    ''' </param>
    Public Sub New(ByVal Owner As Form,
                   Optional TextFont As Font = Nothing,
                   Optional TimeOut As Integer = 0I)

        mOwner = Owner
        mFont = TextFont
        mTimeOut = TimeOut
        Owner.BeginInvoke(New MethodInvoker(AddressOf findDialog))

    End Sub

#End Region

#Region " Private MEthods "

    Private Sub findDialog()

        ' Enumerate windows to find the message box
        If mTries < 0 Then
            Return
        End If

        Dim callback As New NativeMethods.EnumThreadWndProc(AddressOf checkWindow)

        If NativeMethods.EnumThreadWindows(NativeMethods.GetCurrentThreadId(), callback, IntPtr.Zero) Then

            If System.Threading.Interlocked.Increment(mTries) < 10 Then
                mOwner.BeginInvoke(New MethodInvoker(AddressOf findDialog))
            End If

        End If

        If mTimeOut > 0 Then
            TimeoutTimer = New Timer With {.Interval = mTimeOut, .Enabled = True}
            TimeoutTimer.Start()
        End If

    End Sub

    Private Function checkWindow(hWnd As IntPtr, lp As IntPtr) As Boolean

        ' Checks if <hWnd> is a dialog
        Dim sb As New StringBuilder(260)
        NativeMethods.GetClassName(hWnd, sb, sb.Capacity)
        If sb.ToString() <> "#32770" Then Return True

        ' Get the STATIC control that displays the text
        Dim hText As IntPtr = NativeMethods.GetDlgItem(hWnd, &HFFFF)
        Me._MessageBoxWindowHandle = hWnd

        Dim frmRect As New Rectangle(mOwner.Location, mOwner.Size)
        Dim dlgRect As RECT
        NativeMethods.GetWindowRect(hWnd, dlgRect)

        If hText <> IntPtr.Zero Then

            If mFont Is Nothing Then
                ' Get the current font
                mFont = Font.FromHfont(NativeMethods.SendMessage(hText, NativeMethods.WM_GETFONT, IntPtr.Zero, IntPtr.Zero))

            ElseIf mFont IsNot Nothing Then
                NativeMethods.SetWindowPos(hText, 0, 70, 35, frmRect.Width, mFont.Height, 0)

            End If

            NativeMethods.SendMessage(hText, NativeMethods.WM_SETFONT, mFont.ToHfont(), New IntPtr(1))

            ' Resize and positionate the messagebox window:
            NativeMethods.MoveWindow(hWnd,
                                     frmRect.Left + (frmRect.Width - dlgRect.Right + dlgRect.Left) \ 2,
                                     frmRect.Top + (frmRect.Height - dlgRect.Bottom + dlgRect.Top) \ 2,
                                     (dlgRect.Right - dlgRect.Left),
                                     (dlgRect.Bottom - dlgRect.Top), True)

        End If

        ' Done
        Return False

    End Function

#End Region

#Region " Event Handlers "

    Private Sub TimeoutTimer_Tick(ByVal sender As Object, ByVal e As EventArgs) Handles TimeoutTimer.Tick

        NativeMethods.DestroyWindow(Me._MessageBoxWindowHandle)
        Me.Dispose()

    End Sub

#End Region

#Region " IDisposable "

    Public Sub Dispose() Implements IDisposable.Dispose
        mTries = -1
        mOwner = Nothing
        If mFont IsNot Nothing Then mFont.Dispose()
    End Sub

#End Region

End Class

#End Region