摘要：
refCursorcursor）｛boolret＝false；Pointcontrolpoint＝control.PointToClient（Cursor.Position）；control.Size.Width-m_border&；control.Size。Height-m_border）｛type=ResizeType.RightBottom；
这是在昨天的移动控件的基础上增加了拉伸功能
代码看起来长了很多，主要是因为拉伸有8种情况
拉伸时要判断鼠标是否处于边缘，根据位置改变鼠标形状（感觉完全可以由系统直接支持啊）
用法仍然是对控件调用EnableDrag即可
关于Tag，控件都有个Tag，用来放一些用户数据，使用时需要做类型转换，我用Tag存储了控件的位置和大小，方便另外的目的（如何修改代码以便运行，代码中有说明）
class DragControl { private enum ResizeType { Left, Right, Top, Bottom, LeftTop, RightTop, LeftBottom, RightBottom };//拉伸的8种情况 static private int m_border = 5;//边缘宽度 static private ResizeType m_ResizeType;//拉伸操作的边框 static public bool m_OnResize = false;//处于拉伸模式 static public bool m_OnDrag = false;//处于移动模式 static private Point m_LastPoint = new Point();
//入口点，对控件调用这个 static public void EnableDrag(Control control) { //添加事件处理程序 control.MouseDown += new MouseEventHandler(MouseDown); control.MouseMove += new MouseEventHandler(MouseMove); control.MouseUp += new MouseEventHandler(MouseUp); }
//判断鼠标是否处于边缘，获得边缘类型（四条边四个角）以及对应的光标 static private bool isBorder(Control control, Point newpoint,ref ResizeType type,ref Cursor cursor) { bool ret = false; Point controlpoint = control.PointToClient(Cursor.Position); if (controlpoint.X < m_border && controlpoint.Y < m_border) { type = ResizeType.LeftTop; cursor = Cursors.SizeNWSE; ret = true; } else if (controlpoint.X > control.Size.Width - m_border && controlpoint.Y < m_border) { type = ResizeType.RightTop; cursor = Cursors.SizeNESW; ret = true; } else if (controlpoint.X < m_border && controlpoint.Y > control.Size.Height - m_border) { type = ResizeType.LeftBottom; cursor = Cursors.SizeNESW; ret = true; } else if (controlpoint.X > control.Size.Width - m_border && controlpoint.Y > control.Size.Height - m_border) { type = ResizeType.RightBottom; cursor = Cursors.SizeNWSE; ret = true; } else if (controlpoint.X < m_border) { type = ResizeType.Left; cursor = Cursors.SizeWE; ret = true; } else if (controlpoint.X > control.Size.Width - m_border) { type = ResizeType.Right; cursor = Cursors.SizeWE; ret = true; } else if (controlpoint.Y > control.Size.Height - m_border) { type = ResizeType.Bottom; cursor = Cursors.SizeNS; ret = true; } else if (controlpoint.Y < m_border) { type = ResizeType.Top; cursor = Cursors.SizeNS; ret = true; } return ret; } static private void MouseDown(object sender, MouseEventArgs e) { m_OnResize = false; m_OnDrag = false; Control control = (Control)sender; Point newpoint = control.Parent.PointToClient(Cursor.Position); Cursor cursor = new Cursor(Cursor.Current.Handle);//Cursor的构造函数是不需要，但是下面调用的时候要求初始化过，或许这个参数应该用out m_OnResize = isBorder(control, newpoint, ref m_ResizeType, ref cursor); if (m_OnResize) { control.Cursor = cursor; } else {//不是边缘就是移动模式 control.Cursor = Cursors.SizeAll; m_OnDrag = true; } m_LastPoint = newpoint; } static private void MouseMove(object sender, MouseEventArgs e) { Control control = (Control)sender; Point newpoint = control.Parent.PointToClient(Cursor.Position);//当前鼠标位置 if (!m_OnDrag && !m_OnResize) {//还没按下鼠标，只显示光标 Cursor cursor = new Cursor(Cursor.Current.Handle); if (isBorder(control, newpoint, ref m_ResizeType, ref cursor)) { control.Cursor = cursor; } else { control.Cursor = Cursors.Default; } return; } Point moved = new Point(newpoint.X - m_LastPoint.X, newpoint.Y - m_LastPoint.Y);//鼠标位置变化量
//tvi里面放了几个变量，替换了即可
//tvi.m_AutoLocation bool 表明这个对象位置大小是否自动计算（是否经过了定制），就一句代码用到，删掉
//tvi.m_location Point 对象的位置，用临时变量替换即可，初值=control.Location
//tvi.m_size Size 对象的大小，用临时变量替换即可，初值=control.Size
//tvi.m_view 就是对象本身，用control替换即可
TableRelation.TableViewTag tvi = (TableRelation.TableViewTag)control.Tag; tvi.m_AutoLocation = false; if (m_OnDrag) { tvi.m_location.X += moved.X; tvi.m_location.Y += moved.Y; } if (m_OnResize) { switch (m_ResizeType) { case ResizeType.Left: tvi.m_size = new Size(control.Size.Width - moved.X, control.Size.Height); tvi.m_location = new Point(control.Location.X + moved.X, control.Location.Y); break; case ResizeType.Right: tvi.m_size = new Size(control.Size.Width + moved.X, control.Size.Height); break; case ResizeType.Top: tvi.m_size = new Size(control.Size.Width, control.Size.Height - moved.Y); tvi.m_location = new Point(control.Location.X, control.Location.Y + moved.Y); break; case ResizeType.Bottom: tvi.m_size = new Size(control.Size.Width, control.Size.Height + moved.Y); break; case ResizeType.LeftTop: tvi.m_size = new Size(control.Size.Width - moved.X, control.Size.Height - moved.Y); tvi.m_location = new Point(control.Location.X + moved.X, control.Location.Y + moved.Y); break; case ResizeType.LeftBottom: tvi.m_size = new Size(control.Size.Width - moved.X, control.Size.Height + moved.Y); tvi.m_location = new Point(control.Location.X + moved.X, control.Location.Y); break; case ResizeType.RightTop: tvi.m_size = new Size(control.Size.Width + moved.X, control.Size.Height - moved.Y); tvi.m_location = new Point(control.Location.X, control.Location.Y + moved.Y); break; case ResizeType.RightBottom: tvi.m_size = new Size(control.Size.Width + moved.X, control.Size.Height + moved.Y); break; default: MessageBox.Show(m_ResizeType.ToString()); break; } } tvi.m_view.Location = tvi.m_location; tvi.m_view.Size = tvi.m_size; m_LastPoint = newpoint; } static private void MouseUp(object sender, MouseEventArgs e) { Control control = (Control)sender; control.Cursor = Cursors.Default; m_OnResize = false; m_OnDrag = false; } }