PictureBox滚动条、鼠标中轴滚动

PictureBox显示滚动条方法：

　　1.放置在Panl内，panl属性AutoScroll=True

　　2.PictureBox属性Dock为None，Anchor默认值，SizeMode为AutoSize

设置完毕，PictureBox就和Panl共用滚动条了。

通过鼠标滚轮滚动图片，Shift+中轴横向滚动

   Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        '注册窗体鼠标滚动事件
        AddHandler Me.MouseWheel, AddressOf picImg_MouseWheel
    End Sub


    Private Sub picImg_MouseWheel(ByVal sender As Object, ByVal e As MouseEventArgs)
        '获取光标位置
        Dim p As Point = New Point(e.X, e.Y)
        '换算成相对本窗体的位置
        p.Offset(Me.Location.X, Me.Location.Y)
        '判断是否在panel内
        If (Me.Panel1.RectangleToScreen(Panel1.DisplayRectangle).Contains(p)) Then
            'Shift+鼠标，横向滚动
            If Control.ModifierKeys = Keys.Shift Then
                Panel1.AutoScrollPosition = New Point(Panel1.HorizontalScroll.Value - e.Delta, _
                                                      Panel1.VerticalScroll.Value)
            Else
                '竖向滚动
                Panel1.AutoScrollPosition = New Point(Panel1.HorizontalScroll.Value, _
                                                      Panel1.VerticalScroll.Value - e.Delta)
            End If

        End If
    End Sub