运行拖拽时如何判断鼠标在控件的边角上

Question

运行时的活动控件，控件可拖拽和改变大小，鼠标在控件上游走。
当鼠标到达控件边角时，改变光标外观。
如何实现？？

Answer 1

部分代码如下:
private EnumMousePointPosition MousePointPosition(Size size,MouseEventArgs e)
        {
            const int band = 10;
            //鼠标在size区域内时
            if (e.X > -1 * band & e.X <= size.Width & e.Y >= -1 * band && e.Y <= size.Height)
            {
                #region//鼠标在左边时
                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;
                    }
                }
                #endregion
                #region//鼠标在右边时
                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;
                    }
                }
                #endregion
                #region//鼠标在上方时
                if (e.Y < band)
                {
                    return EnumMousePointPosition.MouseSizeTop;
                }
                #endregion
                #region//鼠标在下方时
                else if (e.Y > -1*band + size.Height)
                {
                    return EnumMousePointPosition.MouseSizeBottom;
                }
                #endregion
                #region//鼠标不在上述区域而在Size区域内时
                else
                {
                    return EnumMousePointPosition.MouseDrag;
                }
                #endregion
            }
            //鼠标不在Size区域中
            else
            {
                return EnumMousePointPosition.MouseSizeNone;
            }
        }

Answer 2

我记得有几个API是可以直接拖拉改变控件大小的

Answer 3

这样吧，如果你要处理的都是Window的控件，比如Button,TextBox等，可以从这些控件继承，然后按下的样子来改后再使用控件就可以 了：调整大小位置和鼠标样式都是标准的class ButtonEx : Button//这里可以是任何一个从Coutrol继承的类，（Label除外，因国Label有自己的处理）
{
    private int m_BorderWidth = 4;    internal static int WM_NCHITTEST = 0x84; //移动鼠标，按住或释放鼠标时发生的系统消息
    internal static int WM_NCACTIVATE = 0x86;//窗体的激活状态发生改变的消息    internal static IntPtr HTCLIENT = (IntPtr)0x1;//工作区
    internal static IntPtr HTSYSMENU = (IntPtr)3;//系统菜单
    internal static IntPtr HTCAPTION = (IntPtr)0x2; //标题栏    internal static IntPtr HTLEFT = (IntPtr)10;//向左
    internal static IntPtr HTRIGHT = (IntPtr)11;//向右
    internal static IntPtr HTTOP = (IntPtr)12;//向上
    internal static IntPtr HTTOPLEFT = (IntPtr)13;//向左上
    internal static IntPtr HTTOPRIGHT = (IntPtr)14;//向右上
    internal static IntPtr HTBOTTOM = (IntPtr)15;//向下
    internal static IntPtr HTBOTTOMLEFT = (IntPtr)16;//向左下
    internal static IntPtr HTBOTTOMRIGHT = (IntPtr)17;//向右下    protected override void WndProc(ref Message m)
    {
        if (m.Msg == WM_NCHITTEST)
        {
            base.WndProc(ref m);
            if (DesignMode)
            {
                return;
            }
            if (m.Result == HTCLIENT)
            {
                m.HWnd = this.Handle;                System.Drawing.Rectangle rect = this.RectangleToScreen(this.ClientRectangle);
                Point C_Pos = Cursor.Position;
                if ((Cursor.Position.X <= rect.Left + m_BorderWidth) && (C_Pos.Y <= rect.Top + m_BorderWidth))
                    m.Result = HTTOPLEFT;//左上
                else if ((C_Pos.X >= rect.Left + rect.Width - m_BorderWidth) && (C_Pos.Y <= rect.Top + m_BorderWidth))
                    m.Result = HTTOPRIGHT;//右上
                else if ((C_Pos.X <= rect.Left + m_BorderWidth) && (C_Pos.Y >= rect.Top + rect.Height - m_BorderWidth))
                    m.Result = HTBOTTOMLEFT;//左下
                else if ((C_Pos.X >= rect.Left + rect.Width - m_BorderWidth) && (C_Pos.Y >= rect.Top + rect.Height - m_BorderWidth))
                    m.Result = HTBOTTOMRIGHT;//右下
                else if ((C_Pos.X <= rect.Left + m_BorderWidth - 1))
                    m.Result = HTLEFT;//左
                else if ((C_Pos.X >= rect.Left + rect.Width - m_BorderWidth))
                    m.Result = HTRIGHT;//右
                else if ((C_Pos.Y <= rect.Top + m_BorderWidth - 1))
                    m.Result = HTTOP;//上
                else if ((C_Pos.Y >= rect.Top + rect.Height - m_BorderWidth))
                    m.Result = HTBOTTOM;//下
                else if (C_Pos.Y <= rect.Top + m_BorderWidth)
                {
                    m.Result = HTCAPTION;//模拟标题栏,移动或双击可以最大或最小化窗体
                }
            }
            return;
        }
        base.WndProc(ref m);
    }
}

Answer 4

给你个类文件吧，使用如下的类，可以声明它的一个实例并把要操作的控件传入就行了：
使用上可以这样：//操作button1控件
 MoveableWindow mw = new MoveableWindow(this.Button1);
类的代码：class MoveableWindow : NativeWindow
{
    private int m_BorderWidth = 4;    internal static int WM_NCHITTEST = 0x84; //移动鼠标，按住或释放鼠标时发生的系统消息
    internal static int WM_NCACTIVATE = 0x86;//窗体的激活状态发生改变的消息    internal static IntPtr HTCLIENT = (IntPtr)0x1;//工作区
    internal static IntPtr HTSYSMENU = (IntPtr)3;//系统菜单
    internal static IntPtr HTCAPTION = (IntPtr)0x2; //标题栏    internal static IntPtr HTLEFT = (IntPtr)10;//向左
    internal static IntPtr HTRIGHT = (IntPtr)11;//向右
    internal static IntPtr HTTOP = (IntPtr)12;//向上
    internal static IntPtr HTTOPLEFT = (IntPtr)13;//向左上
    internal static IntPtr HTTOPRIGHT = (IntPtr)14;//向右上
    internal static IntPtr HTBOTTOM = (IntPtr)15;//向下
    internal static IntPtr HTBOTTOMLEFT = (IntPtr)16;//向左下
    internal static IntPtr HTBOTTOMRIGHT = (IntPtr)17;//向右下    private Control m_control;
    public MoveableWindow(Control control)
    {
        m_control = control;
        this.AssignHandle(control.Handle);
    }
    protected override void WndProc(ref Message m)
    {
        if (m.Msg == WM_NCHITTEST)
        {
            base.WndProc(ref m);
            if (m.Result == HTCLIENT)
            {
                m.HWnd = this.Handle;                System.Drawing.Rectangle rect = m_control.RectangleToScreen(m_control.ClientRectangle);
                Point C_Pos = Cursor.Position;
                if ((Cursor.Position.X <= rect.Left + m_BorderWidth) && (C_Pos.Y <= rect.Top + m_BorderWidth))
                    m.Result = HTTOPLEFT;//左上
                else if ((C_Pos.X >= rect.Left + rect.Width - m_BorderWidth) && (C_Pos.Y <= rect.Top + m_BorderWidth))
                    m.Result = HTTOPRIGHT;//右上
                else if ((C_Pos.X <= rect.Left + m_BorderWidth) && (C_Pos.Y >= rect.Top + rect.Height - m_BorderWidth))
                    m.Result = HTBOTTOMLEFT;//左下
                else if ((C_Pos.X >= rect.Left + rect.Width - m_BorderWidth) && (C_Pos.Y >= rect.Top + rect.Height - m_BorderWidth))
                    m.Result = HTBOTTOMRIGHT;//右下
                else if ((C_Pos.X <= rect.Left + m_BorderWidth - 1))
                    m.Result = HTLEFT;//左
                else if ((C_Pos.X >= rect.Left + rect.Width - m_BorderWidth))
                    m.Result = HTRIGHT;//右
                else if ((C_Pos.Y <= rect.Top + m_BorderWidth - 1))
                    m.Result = HTTOP;//上
                else if ((C_Pos.Y >= rect.Top + rect.Height - m_BorderWidth))
                    m.Result = HTBOTTOM;//下
                else
                {
                    m.Result = HTCAPTION;//模拟标题栏,移动或双击可以最大或最小化窗体
                }
            }
            return;
        }
        base.WndProc(ref m);
    }
}

Answer 5

你这样来写吧：希望你能看明白，比较乱
internal enum MouseAction
{
    None,
    CrossLeftTop,
    CrossLeftBottom,
    CrossRightTop,
    CrossRightBottom,
    SizeAll,
    SizeLeft,
    SizeTop,
    SizeRight,
    SizeBottom,
    SizeLeftTop,
    SizeRightTop,
    SizeRightBottom,
    SizeLeftBottom,
}private Rectangle lastBounds;
private Point lastMsPoint;
private Size lastSize;
private void label1_MouseDown(object sender, MouseEventArgs e)
{
    this.lastBounds = this.label1.Bounds;
    this.lastSize = this.label1.Size;
    this.lastMsPoint = Control.MousePosition;
}MouseAction ma = MouseAction.None;
private void label1_MouseMove(object sender, MouseEventArgs e)
{
    Point mp = Control.MousePosition;
    if (!(sender as Label).Capture)
    {
        Rectangle bound = (sender as Label).Bounds;
        ma = this.getAction(bound, this.PointToClient(mp));
        this.SetCursor(ma);
        return;
    }    if (e.Button == MouseButtons.Left)
    {
        switch (ma)
        {
            case MouseAction.SizeAll:
                this.label1.Location = new Point(this.lastBounds.X + mp.X - this.lastMsPoint.X, this.lastBounds.Y + mp.Y - this.lastMsPoint.Y);
                break;
            case MouseAction.SizeLeft:
                this.label1.Bounds = Rectangle.FromLTRB(this.lastBounds.X + mp.X - this.lastMsPoint.X, this.lastBounds.Y, lastBounds.Right, lastBounds.Bottom);
                break;
            case MouseAction.SizeTop:
                this.label1.Bounds = Rectangle.FromLTRB(this.lastBounds.X, this.lastBounds.Y + mp.Y - this.lastMsPoint.Y, lastBounds.Right, lastBounds.Bottom);
                break;
            case MouseAction.SizeRight:
                this.label1.Bounds = Rectangle.FromLTRB(this.lastBounds.X, this.lastBounds.Y + mp.Y - this.lastMsPoint.Y, lastBounds.Right + mp.X - this.lastMsPoint.X, lastBounds.Bottom);
                break;
            case MouseAction.SizeBottom:
                this.label1.Bounds = Rectangle.FromLTRB(this.lastBounds.X, this.lastBounds.Y, lastBounds.Right, lastBounds.Bottom + mp.Y - this.lastMsPoint.Y);
                break;
            case MouseAction.SizeLeftTop:
                this.label1.Bounds = Rectangle.FromLTRB(this.lastBounds.X + mp.X - this.lastMsPoint.X, this.lastBounds.Y + mp.Y - this.lastMsPoint.Y, lastBounds.Right, lastBounds.Bottom);
                break;
            case MouseAction.SizeLeftBottom:
                this.label1.Bounds = Rectangle.FromLTRB(this.lastBounds.X + mp.X - this.lastMsPoint.X, this.lastBounds.Y, lastBounds.Right, lastBounds.Bottom + mp.Y - this.lastMsPoint.Y);
                break;
            case MouseAction.SizeRightBottom:
                this.label1.Bounds = Rectangle.FromLTRB(this.lastBounds.X, this.lastBounds.Y, lastBounds.Right + mp.X - this.lastMsPoint.X, lastBounds.Bottom + mp.Y - this.lastMsPoint.Y);
                break;
            case MouseAction.SizeRightTop:
                this.label1.Bounds = Rectangle.FromLTRB(this.lastBounds.X, this.lastBounds.Y + mp.Y - this.lastMsPoint.Y, lastBounds.Right + mp.X - this.lastMsPoint.X, lastBounds.Bottom);
                break;
        }
    }
}private MouseAction getAction(Rectangle bound, Point e)
{
    int borderWidth = 6;
    Rectangle outerRect = bound;
    Rectangle innerRect = outerRect;
    innerRect.Inflate(-borderWidth, -borderWidth);
    if (innerRect.Contains(e))
    {
        return MouseAction.SizeAll;
    }
    else if (e.X > outerRect.X && e.X < innerRect.X && e.Y > outerRect.Y && e.Y < innerRect.Y)//左上
    {
        return MouseAction.SizeLeftTop;
    }
    else if (e.X < outerRect.Right && e.X > innerRect.Right && e.Y > outerRect.Y && e.Y < innerRect.Y)//右上
    {
        return MouseAction.SizeRightTop;
    }
    else if (e.X > outerRect.X && e.X < innerRect.X && e.Y < outerRect.Bottom && e.Y > innerRect.Bottom)//左下
    {
        return MouseAction.SizeLeftBottom;
    }
    else if (e.X < outerRect.Right && e.X > innerRect.Right && e.Y < outerRect.Bottom && e.Y > innerRect.Bottom)//右下
    {
        return MouseAction.SizeRightBottom;
    }
    else if (e.X > outerRect.X && e.X < innerRect.X)
    {
        return MouseAction.SizeLeft;
    }
    else if (e.X < outerRect.Right && e.X > innerRect.Right)
    {
        return MouseAction.SizeRight;
    }
    else if (e.Y > outerRect.X && e.Y < innerRect.Y)
    {
        return MouseAction.SizeTop;
    }
    else if (e.Y < outerRect.Bottom && e.Y > innerRect.Bottom)
    {
        return MouseAction.SizeBottom;
    }
    return MouseAction.None;
}
private void SetCursor(MouseAction action)
{
    switch (action)
    {
        case MouseAction.None:
            this.Cursor = Cursors.Default;
            break;
        case MouseAction.CrossLeftBottom:
            this.Cursor = Cursors.Cross;
            break;
        case MouseAction.CrossLeftTop:
            this.Cursor = Cursors.Cross;
            break;
        case MouseAction.CrossRightBottom:
            this.Cursor = Cursors.Cross;
            break;
        case MouseAction.CrossRightTop:
            this.Cursor = Cursors.Cross;
            break;
        case MouseAction.SizeAll:
            this.Cursor = Cursors.SizeAll;
            break;
        case MouseAction.SizeBottom:
            this.Cursor = Cursors.SizeNS;
            break;
        case MouseAction.SizeLeft:
            this.Cursor = Cursors.SizeWE;
            break;
        case MouseAction.SizeLeftBottom:
            this.Cursor = Cursors.SizeNESW;
            break;
        case MouseAction.SizeLeftTop:
            this.Cursor = Cursors.SizeNWSE;
            break;
        case MouseAction.SizeRight:
            this.Cursor = Cursors.SizeWE;
            break;
        case MouseAction.SizeRightBottom:
            this.Cursor = Cursors.SizeNWSE;
            break;
        case MouseAction.SizeRightTop:
            this.Cursor = Cursors.SizeNESW;
            break;
        case MouseAction.SizeTop:
            this.Cursor = Cursors.SizeNS;
            break;
        default:
            this.Cursor = Cursors.Default;
            break;
    }
}

Answer 6

因为你那是Label，这个控件在内部代码做了处理，我在上面的代码里做了注了。你再试下新的代码看看吧。

Answer 7

这样吧，我改成了一个类了，这个类从Label继承下来的，你在你的项目里把所有类都换成这个新的Lable类，就可以了。
要做的只是把你的原来的Label类型改成新的Label类型，类代码如下：
internal class SizeableLabel : Label
{
    internal enum MouseAction
    {
        None,
        CrossLeftTop,
        CrossLeftBottom,
        CrossRightTop,
        CrossRightBottom,
        SizeAll,
        SizeLeft,
        SizeTop,
        SizeRight,
        SizeBottom,
        SizeLeftTop,
        SizeRightTop,
        SizeRightBottom,
        SizeLeftBottom,
    }
    private Rectangle lastBounds;
    private Point lastMsPoint;
    private MouseAction ma = MouseAction.None;    protected override void OnMouseDown(MouseEventArgs e)
    {
        base.OnMouseDown(e);
        this.lastBounds = this.Bounds;
        this.lastMsPoint = this.Parent.PointToClient(Control.MousePosition);
    }
    protected override void OnMouseMove(MouseEventArgs e)
    {
        base.OnMouseMove(e);
        Point mp = this.Parent.PointToClient(Control.MousePosition);
        if (!this.Capture)
        {
            Rectangle bound = this.Bounds;
            ma = this.getAction(bound, mp);
            this.setCursor(ma);
            return;
        }        if (e.Button == MouseButtons.Left)
        {
            switch (ma)
            {
                case MouseAction.SizeAll:
                    this.Location = new Point(this.lastBounds.X + mp.X - this.lastMsPoint.X, this.lastBounds.Y + mp.Y - this.lastMsPoint.Y);
                    break;
                case MouseAction.SizeLeft:
                    this.Bounds = Rectangle.FromLTRB(this.lastBounds.X + mp.X - this.lastMsPoint.X, this.lastBounds.Y, lastBounds.Right, lastBounds.Bottom);
                    break;
                case MouseAction.SizeTop:
                    this.Bounds = Rectangle.FromLTRB(this.lastBounds.X, this.lastBounds.Y + mp.Y - this.lastMsPoint.Y, lastBounds.Right, lastBounds.Bottom);
                    break;
                case MouseAction.SizeRight:
                    this.Bounds = Rectangle.FromLTRB(this.lastBounds.X, this.lastBounds.Y + mp.Y - this.lastMsPoint.Y, lastBounds.Right + mp.X - this.lastMsPoint.X, lastBounds.Bottom);
                    break;
                case MouseAction.SizeBottom:
                    this.Bounds = Rectangle.FromLTRB(this.lastBounds.X, this.lastBounds.Y, lastBounds.Right, lastBounds.Bottom + mp.Y - this.lastMsPoint.Y);
                    break;
                case MouseAction.SizeLeftTop:
                    this.Bounds = Rectangle.FromLTRB(this.lastBounds.X + mp.X - this.lastMsPoint.X, this.lastBounds.Y + mp.Y - this.lastMsPoint.Y, lastBounds.Right, lastBounds.Bottom);
                    break;
                case MouseAction.SizeLeftBottom:
                    this.Bounds = Rectangle.FromLTRB(this.lastBounds.X + mp.X - this.lastMsPoint.X, this.lastBounds.Y, lastBounds.Right, lastBounds.Bottom + mp.Y - this.lastMsPoint.Y);
                    break;
                case MouseAction.SizeRightBottom:
                    this.Bounds = Rectangle.FromLTRB(this.lastBounds.X, this.lastBounds.Y, lastBounds.Right + mp.X - this.lastMsPoint.X, lastBounds.Bottom + mp.Y - this.lastMsPoint.Y);
                    break;
                case MouseAction.SizeRightTop:
                    this.Bounds = Rectangle.FromLTRB(this.lastBounds.X, this.lastBounds.Y + mp.Y - this.lastMsPoint.Y, lastBounds.Right + mp.X - this.lastMsPoint.X, lastBounds.Bottom);
                    break;
            }
        }
    }
    private MouseAction getAction(Rectangle bound, Point e)
    {
        int borderWidth = 6;
        Rectangle outerRect = bound;
        Rectangle innerRect = outerRect;
        innerRect.Inflate(-borderWidth, -borderWidth);
        if (innerRect.Contains(e))
        {
            return MouseAction.SizeAll;
        }
        else if (e.X > outerRect.X && e.X < innerRect.X && e.Y > outerRect.Y && e.Y < innerRect.Y)//左上
        {
            return MouseAction.SizeLeftTop;
        }
        else if (e.X < outerRect.Right && e.X > innerRect.Right && e.Y > outerRect.Y && e.Y < innerRect.Y)//右上
        {
            return MouseAction.SizeRightTop;
        }
        else if (e.X > outerRect.X && e.X < innerRect.X && e.Y < outerRect.Bottom && e.Y > innerRect.Bottom)//左下
        {
            return MouseAction.SizeLeftBottom;
        }
        else if (e.X < outerRect.Right && e.X > innerRect.Right && e.Y < outerRect.Bottom && e.Y > innerRect.Bottom)//右下
        {
            return MouseAction.SizeRightBottom;
        }
        else if (e.X > outerRect.X && e.X < innerRect.X)
        {
            return MouseAction.SizeLeft;
        }
        else if (e.X < outerRect.Right && e.X > innerRect.Right)
        {
            return MouseAction.SizeRight;
        }
        else if (e.Y > outerRect.X && e.Y < innerRect.Y)
        {
            return MouseAction.SizeTop;
        }
        else if (e.Y < outerRect.Bottom && e.Y > innerRect.Bottom)
        {
            return MouseAction.SizeBottom;
        }
        return MouseAction.None;
    }    private void setCursor(MouseAction action)
    {
        switch (action)
        {
            case MouseAction.None:
                this.Cursor = Cursors.Default;
                break;
            case MouseAction.CrossLeftBottom:
                this.Cursor = Cursors.Cross;
                break;
            case MouseAction.CrossLeftTop:
                this.Cursor = Cursors.Cross;
                break;
            case MouseAction.CrossRightBottom:
                this.Cursor = Cursors.Cross;
                break;
            case MouseAction.CrossRightTop:
                this.Cursor = Cursors.Cross;
                break;
            case MouseAction.SizeAll:
                this.Cursor = Cursors.SizeAll;
                break;
            case MouseAction.SizeBottom:
                this.Cursor = Cursors.SizeNS;
                break;
            case MouseAction.SizeLeft:
                this.Cursor = Cursors.SizeWE;
                break;
            case MouseAction.SizeLeftBottom:
                this.Cursor = Cursors.SizeNESW;
                break;
            case MouseAction.SizeLeftTop:
                this.Cursor = Cursors.SizeNWSE;
                break;
            case MouseAction.SizeRight:
                this.Cursor = Cursors.SizeWE;
                break;
            case MouseAction.SizeRightBottom:
                this.Cursor = Cursors.SizeNWSE;
                break;
            case MouseAction.SizeRightTop:
                this.Cursor = Cursors.SizeNESW;
                break;
            case MouseAction.SizeTop:
                this.Cursor = Cursors.SizeNS;
                break;
            default:
                this.Cursor = Cursors.Default;
                break;
        }
    }
}