窗体该如何保持重绘？

[Anakin_Skywalker]

我的窗体由于执行了一个长时间计算的函数，常常在函数执行过程中失去响应，也看不见进度条了，窗体一片空白，这样我就没法估计计算时间了。

有没有办法在函数里强制窗体重绘，让我看见进度条啊？

听说Thread.Sleep(1)可以，可是我试过了，窗体仍然会变成一片白

[sx_lxh]

为什么不给长时间计算的函数重开个线程？

[bianchen]

用方法的异步调用，在函数计算的过程中窗体不会变白，窗体上的的进度条也可以继续
　　Private conponents As System.ComponentModel.Container = Nothing
Public Delegate Function MyDelegate() As Integer
Dim iscanceled As Boolean = False
Dim re As Integer
Dim asyncDelegate As New MyDelegate(AddressOf Me.ProcessTask)
Dim ar As IAsyncResult　　
　　Public Function ProcessTask() As Integer
Dim mythread As System.Threading.Thread
Dim i As Integer
For i = 0 To 100
If (Me.iscanceled) Then Exit Function
ProgressBar1.Value = i
mythread.Sleep(100)
Next
Return i
End Function
Public Sub resultsCB(ByVal result As IAsyncResult)
re = asyncDelegate.EndInvoke(ar)
Dim mi As New MethodInvoker(AddressOf Me.updateUI)
Me.BeginInvoke(mi)
End Sub

调用你的计算方法时请写如下代码：
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
Me.iscanceled = False
Me.Cursor = Cursors.WaitCursor
Dim cb As New AsyncCallback(AddressOf Me.resultsCB)
ar = asyncDelegate.BeginInvoke(cb, Nothing)
Me.Cursor = Cursors.Default
End Sub

[Anakin_Skywalker]

非常感谢，虽然我不是全明白，但的确实现了我要的效果

现在倒是因为随时都响应点击等操作，有可能触发新的计算导致数据不一致，不过我把控件控制一下就好啦