vb.net – 创建在另一个线程上运行的进度条,同时在主线程中保持

但是现在出现了一个新问题,一旦尝试向其所有者发送消息,进度窗口就会逐渐消失.有点令人惊讶的是,当您使用Invoke()而不是BeginInvoke()来更新进度时,这个问题有点消失.有点,您仍然可以通过将鼠标移动到禁用所有者的边框上来解决问题.实际上,你必须使用TopMost来确定Z顺序.更现实的是,Windows不支持您尝试做的事情.你知道真正的解决方案,它是你问题的首要问题.

这是一些要试验的代码.假设你的进度形式叫做dlgProgress：

Imports System.Threading

Public Class ShowProgress
  Implements IDisposable
  Private Delegate Sub UpdateProgressDelegate(ByVal pct As Integer)
  Private mOwnerHandle As IntPtr
  Private mOwnerRect As Rectangle
  Private mProgress As dlgProgress
  Private mInterlock As ManualResetEvent

  Public Sub New(ByVal owner As Form)
    Debug.Assert(owner.Created)
    mOwnerHandle = owner.Handle
    mOwnerRect = owner.Bounds
    mInterlock = New ManualResetEvent(False)
    Dim t As Thread = New Thread(AddressOf dlgStart)
    t.SetApartmentState(ApartmentState.STA)
    t.Start()
    mInterlock.WaitOne()
  End Sub

  Public Sub Dispose() Implements IDisposable.Dispose
    mProgress.BeginInvoke(New MethodInvoker(AddressOf dlgClose))
  End Sub

  Public Sub UpdateProgress(ByVal pct As Integer)
    mProgress.Invoke(New UpdateProgressDelegate(AddressOf dlgUpdate),pct)
  End Sub

  Private Sub dlgStart()
    mProgress = New dlgProgress
    mProgress.StartPosition = FormStartPosition.Manual
    mProgress.ShowInTaskbar = False
    AddHandler mProgress.Load,AddressOf dlgLoad
    AddHandler mProgress.FormClosing,AddressOf dlgClosing
    EnableWindow(mOwnerHandle,False)
    SetWindowLong(mProgress.Handle,-8,mOwnerHandle)
    Application.Run(mProgress)
  End Sub

  Private Sub dlgLoad(ByVal sender As Object,ByVal e As EventArgs)
    mProgress.Location = New Point( _
      mOwnerRect.Left + (mOwnerRect.Width - mProgress.Width)  2,_
      mOwnerRect.Top + (mOwnerRect.Height - mProgress.Height)  2)
    mInterlock.Set()
  End Sub

  Private Sub dlgUpdate(ByVal pct As Integer)
    mProgress.ProgressBar1.Value = pct
  End Sub

  Private Sub dlgClosing(ByVal sender As Object,ByVal e As FormClosingEventArgs)
    EnableWindow(mOwnerHandle,True)
  End Sub

  Private Sub dlgClose()
    mProgress.Close()
    mProgress = Nothing
  End Sub

  '--- P/Invoke
  Public Shared Function SetWindowLong(ByVal hWnd As IntPtr,ByVal nIndex As Integer,ByVal dwNewLong As IntPtr) As IntPtr
    If IntPtr.Size = 4 Then
      Return SetWindowLongPtr32(hWnd,nIndex,dwNewLong)
    Else
      Return SetWindowLongPtr64(hWnd,dwNewLong)
    End If
  End Function

  Private Declare Function EnableWindow Lib "user32.dll" (ByVal hWnd As IntPtr,ByVal enabled As Boolean) As Boolean
  Private Declare Function SetWindowLongPtr32 Lib "user32.dll" Alias "SetWindowLongW" (ByVal hWnd As IntPtr,ByVal dwNewLong As IntPtr) As IntPtr
  Private Declare Function SetWindowLongPtr64 Lib "user32.dll" Alias "SetWindowLongW" (ByVal hWnd As IntPtr,ByVal dwNewLong As IntPtr) As IntPtr

End Class

样品用法：

Private Sub Button1_Click(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles Button1.Click
    Using dlg As New ShowProgress(Me)
      For ix As Integer = 1 To 100
        dlg.UpdateProgress(ix)
        System.Threading.Thread.Sleep(50)
      Next
    End Using
  End Sub