const int BAND = 5;
const int MINWIDTH = 10;
const int MINHEIGHT = 10;
private EnumMousePointPosition m_MousePointPosition;
private Point p1, p2;


/// <summary>
/// 光标状态
/// </summary>
private enum EnumMousePointPosition
{
    MouseSizeNone = 0, //'无
    MouseSizeRight = 1, //'拉伸右边框
    MouseSizeLeft = 2, //'拉伸左边框
    MouseSizeBottom = 3, //'拉伸下边框
    MouseSizeTop = 4, //'拉伸上边框
    MouseSizeTopLeft = 5, //'拉伸左上角
    MouseSizeTopRight = 6, //'拉伸右上角
    MouseSizeBottomLeft = 7, //'拉伸左下角
    MouseSizeBottomRight = 8, //'拉伸右下角
    MouseDrag = 9  // '鼠标拖动
}

/// <summary>
/// 确定光标在控件不同位置的样式
/// </summary>
/// <param name="size"></param>
/// <param name="e"></param>
/// <returns></returns>
private EnumMousePointPosition MousePointPosition(Size size, System.Windows.Forms.MouseEventArgs e)
{

    if ((e.X >= -1 * BAND) | (e.X <= size.Width) | (e.Y >= -1 * BAND) | (e.Y <= size.Height))
    {
        if (e.X < BAND)
        {
            if (e.Y < BAND) { return EnumMousePointPosition.MouseSizeTopLeft; }
            else
            {
                if (e.Y > -1 * BAND + size.Height)
                { return EnumMousePointPosition.MouseSizeBottomLeft; }
                else
                { return EnumMousePointPosition.MouseSizeLeft; }
            }
        }
        else
        {
            if (e.X > -1 * BAND + size.Width)
            {
                if (e.Y < BAND)
                { return EnumMousePointPosition.MouseSizeTopRight; }
                else
                {
                    if (e.Y > -1 * BAND + size.Height)
                    { return EnumMousePointPosition.MouseSizeBottomRight; }
                    else
                    { return EnumMousePointPosition.MouseSizeRight; }
                }
            }
            else
            {
                if (e.Y < BAND)
                { return EnumMousePointPosition.MouseSizeTop; }
                else
                {
                    if (e.Y > -1 * BAND + size.Height)
                    { return EnumMousePointPosition.MouseSizeBottom; }
                    else
                    { return EnumMousePointPosition.MouseDrag; }
                }
            }
        }
    }
    else
    { return EnumMousePointPosition.MouseSizeNone; }
}

/// <summary>
/// MouseDown事件处理程序
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void MyMouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
{
    p1.X = e.X;
    p1.Y = e.Y;

    p2.X = e.X;
    p2.Y = e.Y;
}

/// <summary>
/// MouseLeave事件处理程序
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void MyMouseLeave(object sender, System.EventArgs e)
{
    m_MousePointPosition = EnumMousePointPosition.MouseSizeNone;
    this.Cursor = Cursors.Arrow;
}

/// <summary>
/// MouseMove事件处理程序
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void MyMouseMove(object sender, System.Windows.Forms.MouseEventArgs e)
{
    Control lCtrl = (sender as Control);

    if (e.Button == MouseButtons.Left)
    {
        switch (m_MousePointPosition)
        {
            case EnumMousePointPosition.MouseDrag:
                lCtrl.Left = lCtrl.Left + e.X - p1.X;
                lCtrl.Top = lCtrl.Top + e.Y - p1.Y;
                break;
            case EnumMousePointPosition.MouseSizeBottom:
                lCtrl.Height = lCtrl.Height + e.Y - p2.Y;
                p2.X = e.X;
                p2.Y = e.Y; //'记录光标拖动的当前点
                break;
            case EnumMousePointPosition.MouseSizeBottomRight:
                lCtrl.Width = lCtrl.Width + e.X - p2.X;
                lCtrl.Height = lCtrl.Height + e.Y - p2.Y;
                p2.X = e.X;
                p2.Y = e.Y; //'记录光标拖动的当前点
                break;
            case EnumMousePointPosition.MouseSizeRight:
                lCtrl.Width = lCtrl.Width + e.X - p2.X;
                //      lCtrl.Height = lCtrl.Height + e.Y - p1.Y;
                p2.X = e.X;
                p2.Y = e.Y; //'记录光标拖动的当前点
                break;
            case EnumMousePointPosition.MouseSizeTop:
                lCtrl.Top = lCtrl.Top + (e.Y - p1.Y);
                lCtrl.Height = lCtrl.Height - (e.Y - p1.Y);
                break;
            case EnumMousePointPosition.MouseSizeLeft:
                lCtrl.Left = lCtrl.Left + e.X - p1.X;
                lCtrl.Width = lCtrl.Width - (e.X - p1.X);
                break;
            case EnumMousePointPosition.MouseSizeBottomLeft:
                lCtrl.Left = lCtrl.Left + e.X - p1.X;
                lCtrl.Width = lCtrl.Width - (e.X - p1.X);
                lCtrl.Height = lCtrl.Height + e.Y - p2.Y;
                p2.X = e.X;
                p2.Y = e.Y; //'记录光标拖动的当前点
                break;
            case EnumMousePointPosition.MouseSizeTopRight:
                lCtrl.Top = lCtrl.Top + (e.Y - p1.Y);
                lCtrl.Width = lCtrl.Width + (e.X - p2.X);
                lCtrl.Height = lCtrl.Height - (e.Y - p1.Y);
                p2.X = e.X;
                p2.Y = e.Y; //'记录光标拖动的当前点
                break;
            case EnumMousePointPosition.MouseSizeTopLeft:
                lCtrl.Left = lCtrl.Left + e.X - p1.X;
                lCtrl.Top = lCtrl.Top + (e.Y - p1.Y);
                lCtrl.Width = lCtrl.Width - (e.X - p1.X);
                lCtrl.Height = lCtrl.Height - (e.Y - p1.Y);
                break;
            default:
                break;
        }
        if (lCtrl.Width < MINWIDTH) lCtrl.Width = MINWIDTH;
        if (lCtrl.Height < MINHEIGHT) lCtrl.Height = MINHEIGHT;

    }
    else
    {
        m_MousePointPosition = MousePointPosition(lCtrl.Size, e);  //'判断光标的位置状态
        switch (m_MousePointPosition)  //'改变光标
        {
            case EnumMousePointPosition.MouseSizeNone:
                this.Cursor = Cursors.Arrow;       //'箭头
                break;
            case EnumMousePointPosition.MouseDrag:
                this.Cursor = Cursors.SizeAll;     //'四方向
                break;
            case EnumMousePointPosition.MouseSizeBottom:
                this.Cursor = Cursors.SizeNS;      //'南北
                break;
            case EnumMousePointPosition.MouseSizeTop:
                this.Cursor = Cursors.SizeNS;      //'南北
                break;
            case EnumMousePointPosition.MouseSizeLeft:
                this.Cursor = Cursors.SizeWE;      //'东西
                break;
            case EnumMousePointPosition.MouseSizeRight:
                this.Cursor = Cursors.SizeWE;      //'东西
                break;
            case EnumMousePointPosition.MouseSizeBottomLeft:
                this.Cursor = Cursors.SizeNESW;    //'东北到南西
                break;
            case EnumMousePointPosition.MouseSizeBottomRight:
                this.Cursor = Cursors.SizeNWSE;    //'东南到西北
                break;
            case EnumMousePointPosition.MouseSizeTopLeft:
                this.Cursor = Cursors.SizeNWSE;    //'东南到西北
                break;
            case EnumMousePointPosition.MouseSizeTopRight:
                this.Cursor = Cursors.SizeNESW;    //'东北到南西
                break;
            default:
                break;
        }
    }
}

pictureBox1.MouseDown += new System.Windows.Forms.MouseEventHandler(MyMouseDown);
pictureBox1.MouseLeave += new System.EventHandler(MyMouseLeave);
pictureBox1.MouseMove += new System.Windows.Forms.MouseEventHandler(MyMouseMove);