drawimage会触发什么事件？

timezone 2011-03-01 12:38:59

我想知道
g2 = Graphics.FromImage(bgimage)
g2.DrawImage(My.Resources.tr, 0, 0)
PictureBox1.Image = bgimage
当这个g2调用drawimage时会触发一个什么事件？因为我发现用timer来实现PictureBox1.Image = bgimage
还是无法获取多个线程在这个图片上实时的操作结果，如果不用timer也不可能我每一次操作drawimage就让它给pictureobx.image赋值一下,因为用drawimage的地方太多了。如果能知道drawimage会触发什么事件应当就好办了。请教高手指点！具体我为什么要这么做请看我这个贴子：
http://topic.csdn.net/u/20110217/19/e36e6525-a089-48a0-9ede-88752cb9d07f.html

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timezone 2011-03-01

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恳请高手出来指点一下啊

xingyuebuyu 2011-03-01

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drawimage不会触发事件的，界面上的图片方字是收到WM_PAINT消息后才重绘的，你目前是绘制完后才显示到界面上，需求不一样，绘制完后必须去刷新才行。
如果想实时显示，在每进行一次DRAW动作后都需要刷新的

Imports System.Threading

Imports System.ComponentModel



Public Class Form1



    Dim g2 As Graphics

    Dim xp1 As Bitmap = New Bitmap("d:\1.bmp")

    Dim xp2 As Bitmap = New Bitmap("d:\112.bmp")

    Dim bgimage As Bitmap



    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load



        bgimage = New Bitmap(PictureBox1.Width, PictureBox1.Height) '创建相同大小的内存位图

        g2 = Graphics.FromImage(bgimage)

        PictureBox1.Image = bgimage

        'g2.DrawImage(My.Resources.tr, 0, 0)

    End Sub



    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Dim t1 As New Thread(AddressOf thread1)

        Dim isy As ISynchronizeInvoke = Me

        t1.Start(isy)

    End Sub



    Private Sub thread1(ByVal obj As Object)

        Dim isy As ISynchronizeInvoke = obj

        isy.BeginInvoke(New MethodInvoker(AddressOf work), Nothing)

    End Sub



    Public bolSwitch As Boolean = False

    Public Sub work()

        For a As Integer = 1 To 10000000

            bolSwitch = Not bolSwitch

            If bolSwitch = True Then

                g2.DrawImage(xp1, 20, 20)

            Else

                g2.DrawImage(xp2, 20, 20)

            End If



            g2.DrawString(Guid.NewGuid.ToString, SystemFonts.CaptionFont, Brushes.Blue, 40, 40)



            PictureBox1.Invalidate()

            'PictureBox1.Image = bgimage

            Thread.Sleep(1)

            Application.DoEvents()

        Next

    End Sub



End Class