using System;  using System.Windows.Forms;  using System.Drawing;  namespace ControlSizeChangeEx  {      /// <summary>      /// This class implements sizing and moving functions for      /// runtime editing of graphic controls      /// </summary>      public class PickBox      {          //////////////////////////////////////////////////////////////////          // PRIVATE CONSTANTS AND VARIABLES          //////////////////////////////////////////////////////////////////          private const int BOX_SIZE = 8;          private Color BOX_COLOR = Color.White;          private ContainerControl m_container;          private Control m_control;          private Label[] lbl = new Label[8];          private int startl;          private int startt;          private int startw;          private int starth;          private int startx;          private int starty;          private bool dragging;          private Cursor[] arrArrow = new Cursor[] {Cursors.SizeNWSE, Cursors.SizeNS,     Cursors.SizeNESW, Cursors.SizeWE, Cursors.SizeNWSE, Cursors.SizeNS,     Cursors.SizeNESW, Cursors.SizeWE};          private Cursor oldCursor;          private const int MIN_SIZE = 20;          //          // Constructor creates 8 sizing handles & wires mouse events          // to each that implement sizing functions          //          public PickBox()          {              for (int i = 0; i < 8; i++)              {                  lbl[i] = new Label();                  lbl[i].TabIndex = i;                  lbl[i].FlatStyle = 0;                  lbl[i].BorderStyle = BorderStyle.FixedSingle;                  lbl[i].BackColor = BOX_COLOR;                  lbl[i].Cursor = arrArrow[i];                  lbl[i].Text = "";                  lbl[i].BringToFront();                  lbl[i].MouseDown += new MouseEventHandler(this.lbl_MouseDown);                  lbl[i].MouseMove += new MouseEventHandler(this.lbl_MouseMove);                  lbl[i].MouseUp += new MouseEventHandler(this.lbl_MouseUp);              }          }          //////////////////////////////////////////////////////////////////          // PUBLIC METHODS          //////////////////////////////////////////////////////////////////          //          // Wires a Click event handler to the passed Control          // that attaches a pick box to the control when it is clicked          //          public void WireControl(Control ctl)          {              ctl.Click += new EventHandler(this.SelectControl);          }          /////////////////////////////////////////////////////////////////          // PRIVATE METHODS          /////////////////////////////////////////////////////////////////          //          // Attaches a pick box to the sender Control          //          private void SelectControl(object sender, EventArgs e)          {              if (m_control is Control)              {                  m_control.Cursor = oldCursor;                  //Remove event any pre-existing event handlers appended by this class                  m_control.MouseDown -= new MouseEventHandler(this.ctl_MouseDown);                  m_control.MouseMove -= new MouseEventHandler(this.ctl_MouseMove);                  m_control.MouseUp -= new MouseEventHandler(this.ctl_MouseUp);                  m_control = null;              }              m_control = (Control)sender;              //Add event handlers for moving the selected control around              m_control.MouseDown += new MouseEventHandler(this.ctl_MouseDown);              m_control.MouseMove += new MouseEventHandler(this.ctl_MouseMove);              m_control.MouseUp += new MouseEventHandler(this.ctl_MouseUp);              //Add sizing handles to Control‘s <a href="http://www.mamicode.com/http://lib.csdn.net/base/docker" class=‘replace_word‘ title="Docker知识库" target=‘_blank‘ style=‘color:#df3434; font-weight:bold;‘>Container</a> (Form or PictureBox)              for (int i = 0; i < 8; i++)              {                  m_control.Parent.Controls.Add(lbl[i]);                  lbl[i].BringToFront();              }              //Position sizing handles around Control              MoveHandles();              //Display sizing handles              ShowHandles();              oldCursor = m_control.Cursor;              m_control.Cursor = Cursors.SizeAll;          }          public void Remove()          {              HideHandles();              m_control.Cursor = oldCursor;          }          private void ShowHandles()          {              if (m_control != null)              {                  for (int i = 0; i < 8; i++)                  {                      lbl[i].Visible = true;                  }              }          }          private void HideHandles()          {              for (int i = 0; i < 8; i++)              {                  lbl[i].Visible = false;              }          }          private void MoveHandles()          {              int sX = m_control.Left - BOX_SIZE;              int sY = m_control.Top - BOX_SIZE;              int sW = m_control.Width + BOX_SIZE;              int sH = m_control.Height + BOX_SIZE;              int hB = BOX_SIZE / 2;              int[] arrPosX = new int[] {sX+hB, sX + sW / 2, sX + sW-hB, sX + sW-hB,     sX + sW-hB, sX + sW / 2, sX+hB, sX+hB};              int[] arrPosY = new int[] {sY+hB, sY+hB, sY+hB, sY + sH / 2, sY + sH-hB,     sY + sH-hB, sY + sH-hB, sY + sH / 2};              for (int i = 0; i < 8; i++)                  lbl[i].SetBounds(arrPosX[i], arrPosY[i], BOX_SIZE, BOX_SIZE);          }          /////////////////////////////////////////////////////////////////          // MOUSE EVENTS THAT IMPLEMENT SIZING OF THE PICKED CONTROL          /////////////////////////////////////////////////////////////////          //          // Store control position and size when mouse button pushed over          // any sizing handle          //          private void lbl_MouseDown(object sender, MouseEventArgs e)          {              dragging = true;              startl = m_control.Left;              startt = m_control.Top;              startw = m_control.Width;              starth = m_control.Height;              HideHandles();          }          //          // Size the picked control in accordance with sizing handle being dragged          // 0   1   2          //  7       3          //  6   5   4          //          private void lbl_MouseMove(object sender, MouseEventArgs e)          {              int l = m_control.Left;              int w = m_control.Width;              int t = m_control.Top;              int h = m_control.Height;              if (dragging)              {                  switch (((Label)sender).TabIndex)                  {                      case 0: // Dragging top-left sizing box                          l = startl + e.X < startl + startw - MIN_SIZE ? startl + e.X : startl + startw - MIN_SIZE;                          t = startt + e.Y < startt + starth - MIN_SIZE ? startt + e.Y : startt + starth - MIN_SIZE;                          w = startl + startw - m_control.Left;                          h = startt + starth - m_control.Top;                          break;                      case 1: // Dragging top-center sizing box                          t = startt + e.Y < startt + starth - MIN_SIZE ? startt + e.Y : startt + starth - MIN_SIZE;                          h = startt + starth - m_control.Top;                          break;                      case 2: // Dragging top-right sizing box                          w = startw + e.X > MIN_SIZE ? startw + e.X : MIN_SIZE;                          t = startt + e.Y < startt + starth - MIN_SIZE ? startt + e.Y : startt + starth - MIN_SIZE;                          h = startt + starth - m_control.Top;                          break;                      case 3: // Dragging right-middle sizing box                          w = startw + e.X > MIN_SIZE ? startw + e.X : MIN_SIZE;                          break;                      case 4: // Dragging right-bottom sizing box                          w = startw + e.X > MIN_SIZE ? startw + e.X : MIN_SIZE;                          h = starth + e.Y > MIN_SIZE ? starth + e.Y : MIN_SIZE;                          break;                      case 5: // Dragging center-bottom sizing box                          h = starth + e.Y > MIN_SIZE ? starth + e.Y : MIN_SIZE;                          break;                      case 6: // Dragging left-bottom sizing box                          l = startl + e.X < startl + startw - MIN_SIZE ? startl + e.X : startl + startw - MIN_SIZE;                          w = startl + startw - m_control.Left;                          h = starth + e.Y > MIN_SIZE ? starth + e.Y : MIN_SIZE;                          break;                      case 7: // Dragging left-middle sizing box                          l = startl + e.X < startl + startw - MIN_SIZE ? startl + e.X : startl + startw - MIN_SIZE;                          w = startl + startw - m_control.Left;                          break;                  }                  l = (l < 0) ? 0 : l;                  t = (t < 0) ? 0 : t;                  m_control.SetBounds(l, t, w, h);              }          }          //          // Display sizing handles around picked control once sizing has completed          //          private void lbl_MouseUp(object sender, MouseEventArgs e)          {              dragging = false;              MoveHandles();              ShowHandles();          }          /////////////////////////////////////////////////////////////////          // MOUSE EVENTS THAT MOVE THE PICKED CONTROL AROUND THE FORM          /////////////////////////////////////////////////////////////////          //          // Get mouse pointer starting position on mouse down and hide sizing handles          //          private void ctl_MouseDown(object sender, MouseEventArgs e)          {              dragging = true;              startx = e.X;              starty = e.Y;              HideHandles();          }          //          // Reposition the dragged control          //          private void ctl_MouseMove(object sender, MouseEventArgs e)          {              if (dragging)              {                  int l = m_control.Left + e.X - startx;                  int t = m_control.Top + e.Y - starty;                  int w = m_control.Width;                  int h = m_control.Height;                  l = (l < 0) ? 0 : ((l + w > m_control.Parent.ClientRectangle.Width) ?                    m_control.Parent.ClientRectangle.Width - w : l);                  t = (t < 0) ? 0 : ((t + h > m_control.Parent.ClientRectangle.Height) ?                  m_control.Parent.ClientRectangle.Height - h : t);                  m_control.Left = l;                  m_control.Top = t;              }          }          //          // Display sizing handles around picked control once dragging has completed          //          private void ctl_MouseUp(object sender, MouseEventArgs e)          {              dragging = false;              MoveHandles();              ShowHandles();          }      }  }