.net中PictureBox中圖片的拖動

.net中PictureBox中圖片的拖動
首先在Form窗體上放一個PictureBox，并指定一個圖片顯示

定義一系列變量處理圖片拖動
 '處理圖片拖動
        Private m_Leftx As Integer
        Private m_Lefty As Integer
        Dim m_MousePosX As Integer
        Dim m_MousePosY As Integer
        Dim m_DriftX As Integer
        Dim m_DriftY As Integer
并給賦初值，可以在Form初始化時做
  Me.m_Leftx = Me.PictureBox1.Location.X
        Me.m_Lefty = Me.PictureBox1.Location.Y

定義處理鼠標按下的事件

 '當鼠標按下時，將鼠標變成手形，并且記錄下當前鼠標的位置
  Private Sub PictureBox1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseDown

            Me.Cursor = System.Windows.Forms.Cursors.Hand
            m_MousePosX = e.X
            m_MousePosY = e.Y

        End Sub
定義處理鼠標抬起的事件
 '處理鼠標按鍵抬起的事件，根據(jù)鼠標按下時保存的鼠標位置，和當前鼠標的位置，計算鼠標移動偏移量，借此調(diào)用移動圖片的函數(shù)，移動圖片
        Private Sub PictureBox1_MouseUp(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseUp
          
            m_DriftX = m_MousePosX - e.X
            m_DriftY = m_MousePosY - e.Y
         
            m_Leftx = m_Leftx - m_DriftX
            m_Lefty = m_Lefty - m_DriftY
          
            picturemove(sender, e)
            Me.Cursor = System.Windows.Forms.Cursors.Arrow

        End Sub

 '根據(jù)偏移量計算出的圖片位置，重畫圖片
        Private Sub picturemove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs)
            Dim myBit As New System.Drawing.Bitmap(PictureBox1.Image)

            Dim myPicGrh As System.Drawing.Graphics = Me.PictureBox1.CreateGraphics
            myPicGrh.Clear(Me.PictureBox1.BackColor)
           
            myPicGrh.DrawImageUnscaled(myBit, m_Leftx - 152, m_Lefty)

            myBit.Dispose()
            myPicGrh.Dispose()

        End Sub