Question

我有很多Splash Form，MDIParent Form和其他形式。我的场景流程如下：Project Statup - SPlash Form，After Splash Form第一次显示并检查一些文件等，检查后将显示MDIParent1并且splash表单将自动关闭。

以下是我在Splash表单中的代码：

Public Class frmSplash
Dim m_CountTo As Integer = 0 ' How many time to loop.
Private Sub My_BgWorker_DoWork(ByVal sender As Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles My_BgWorker.DoWork

    For i As Integer = 0 To m_CountTo
        ' Has the background worker be told to stop?
        If My_BgWorker.CancellationPending Then
            ' Set Cancel to True
            e.Cancel = True
            Exit For
        End If
        System.Threading.Thread.Sleep(100) ' Sleep for 1 Second
        ' Report The progress of the Background Worker.
        My_BgWorker.ReportProgress(CInt((i / m_CountTo) * 100))
        SetLabelText_ThreadSafe(Me.lblPercent, FormatPercent(i / m_CountTo, 2))

        If i = 10 Then
            SetLabelText_ThreadSafe(Me.lblMessages, "Initializing..")

        ElseIf i = 40 Then
            SetLabelText_ThreadSafe(Me.lblMessages, "Checking Mysql Service..")
        ElseIf i = 50 Then
            If CheckIfServiceIsRunning("MySql") = False Then
                ' Is the Background Worker do some work?
                If My_BgWorker.IsBusy Then
                    'If it supports cancellation, Cancel It
                    If My_BgWorker.WorkerSupportsCancellation Then
                        ' Tell the Background Worker to stop working.
                        My_BgWorker.CancelAsync()
                    End If
                End If

                SetButton_ThreadSafe(Me.btnExit, True)
                Exit Sub
            End If
        ElseIf i = 70 Then
            SetLabelText_ThreadSafe(Me.lblMessages, "Checking Internet Connection..")
        ElseIf i = 80 Then
            If CheckURL("http://www.google.com") = False Then
                SetLabelText_ThreadSafe(Me.lblMessages, "No Internet Connection..")
            End If
Next
End Sub

Private Sub My_BgWorker_ProgressChanged(ByVal sender As Object, ByVal e As System.ComponentModel.ProgressChangedEventArgs) Handles My_BgWorker.ProgressChanged
    ' Update the progress bar
    Me.ProgressBar1.Value = e.ProgressPercentage
End Sub
Private Sub My_BgWorker_RunWorkerCompleted(ByVal sender As Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles My_BgWorker.RunWorkerCompleted
    If e.Cancelled Then
        Me.lblMessages.Text = "Cancelled"
    Else
        Me.lblMessages.Text = "Completed"
        My_BgWorker.CancelAsync()
        Me.Close()
        MDIParent1.Show()

    End If
End Sub
Delegate Sub SetLabelText_Delegate(ByVal [Label] As Label, ByVal [text] As String)

' The delegates subroutine.
Private Sub SetLabelText_ThreadSafe(ByVal [Label] As Label, ByVal [text] As String)
    ' InvokeRequired required compares the thread ID of the calling thread to the thread ID of the creating thread.
    ' If these threads are different, it returns true.
    If [Label].InvokeRequired Then
        Dim MyDelegate As New SetLabelText_Delegate(AddressOf SetLabelText_ThreadSafe)
        Me.Invoke(MyDelegate, New Object() {[Label], [text]})
    Else
        [Label].Text = [text]
    End If
End Sub
Delegate Sub SetButton_Delegate(ByVal [Button] As Button, ByVal [visible] As Boolean)

' The delegates subroutine.
Private Sub SetButton_ThreadSafe(ByVal [Button] As Button, ByVal [visible] As Boolean)
    ' InvokeRequired required compares the thread ID of the calling thread to the thread ID of the creating thread.
    ' If these threads are different, it returns true.
    If [Button].InvokeRequired Then
        Dim MyDelegate As New SetButton_Delegate(AddressOf SetButton_ThreadSafe)
        Me.Invoke(MyDelegate, New Object() {[Button], [visible]})
    Else
        [Button].Visible = [visible]
    End If
End Sub
Private Sub frmSplash_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

    'Set the count to 100
    m_CountTo = 100
    ' Start the Background Worker working
    My_BgWorker.RunWorkerAsync()
End Sub
Private Sub btnExit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnExit.Click
    ' Is the Background Worker do some work?
    If My_BgWorker.IsBusy Then
        'If it supports cancellation, Cancel It
        If My_BgWorker.WorkerSupportsCancellation Then
            ' Tell the Background Worker to stop working.
            My_BgWorker.CancelAsync()
        End If
    End If
    ' Enable to Start Button
    Me.btnExit.Enabled = True
    ' Disable to Stop Button
    Me.btnExit.Enabled = False
    Application.Exit()
End Sub

结束班

任何人都可以帮助我，在完成初始化表单加载之后，最好的方法是在子RunWorkerCompleted中显示MDIParent（主窗体）。在上面的代码中，MDIParent1无法正确显示，因为在show之后，应用程序已关闭/终止。

Answer 1

在项目中 - ＆gt;属性，将您的MDIParent设置为“启动表单”，并将您的启动表格设置为“启动表单”。

现在使用任何线程或BackgroundWorkers将所有初始化检查放在MDIParent 的Load（）事件中，不带。只要Load（）事件完成，Splash Form就会显示，然后自动关闭。

要更新MDIParent的启动，请将My.Application.SplashScreen转换为您的启动窗体类型，并使用委托/调用（），就像您现在一样。

这是一个愚蠢的例子：

Public Class frmMdiParent

    Private Sub frmMdiParent_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        ' initialization...
        Dim splash As frmSplash = DirectCast(My.Application.SplashScreen, frmSplash)
        Dim numberSteps As Integer = 10
        For i As Integer = 1 To numberSteps
            splash.Invoke(Sub()
                              splash.Label1.Text = "Step " & i & " of " & numberSteps
                          End Sub)
            System.Threading.Thread.Sleep(1000)
        Next

        ' some other stuff...
        Dim child As New Form
        child.MdiParent = Me
        child.Text = "Some MdiChild..."
        child.Show()
    End Sub

End Class

如何在VB.NET中运行RunWorkerCompleted后显示或加载主窗体（MDIParent1）

1 个答案: