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DockPanel.DragHandler.cs
资源名称：WeifenLuo.WinFormsUI.Docking.rar　[点击查看]
上传用户：szlfmled
上传日期：2020-11-22
资源大小：978k
文件大小：4k
源码类别：

C#编程

开发平台：

C#

DockPanel.DragHandler.cs：源码内容
  1. using System;
  2. using System.Collections.Generic;
  3. using System.Text;
  4. using System.Windows.Forms;
  5. using System.Drawing;
  6. using System.Drawing.Drawing2D;
  7. using System.ComponentModel;
  9. namespace WeifenLuo.WinFormsUI.Docking
  10. {
  11.     partial class DockPanel
  12.     {
  13.         /// <summary>
  14.         /// DragHandlerBase is the base class for drag handlers. The derived class should:
  15.         ///   1. Define its public method BeginDrag. From within this public BeginDrag method,
  16.         ///      DragHandlerBase.BeginDrag should be called to initialize the mouse capture
  17.         ///      and message filtering.
  18.         ///   2. Override the OnDragging and OnEndDrag methods.
  19.         /// </summary>
  20.         private abstract class DragHandlerBase : NativeWindow, IMessageFilter
  21.         {
  22.             protected DragHandlerBase()
  23.             {
  24.             }
  26.             protected abstract Control DragControl
  27.             {
  28.                 get;
  29.             }
  31.             private Point m_startMousePosition = Point.Empty;
  32.             protected Point StartMousePosition
  33.             {
  34.                 get { return m_startMousePosition; }
  35.                 private set { m_startMousePosition = value; }
  36.             }
  38.             protected bool BeginDrag()
  39.             {
  40.                 // Avoid re-entrance;
  41.                 lock (this)
  42.                 {
  43.                     if (DragControl == null)
  44.                         return false;
  46.                     StartMousePosition = Control.MousePosition;
  48.                     if (!NativeMethods.DragDetect(DragControl.Handle, StartMousePosition))
  49.                         return false;
  51.                     DragControl.FindForm().Capture = true;
  52.                     AssignHandle(DragControl.FindForm().Handle);
  53.                     Application.AddMessageFilter(this);
  54.                     return true;
  55.                 }
  56.             }
  58.             protected abstract void OnDragging();
  60.             protected abstract void OnEndDrag(bool abort);
  62.             private void EndDrag(bool abort)
  63.             {
  64.                 ReleaseHandle();
  65.                 Application.RemoveMessageFilter(this);
  66.                 DragControl.FindForm().Capture = false;
  68.                 OnEndDrag(abort);
  69.             }
  71.             bool IMessageFilter.PreFilterMessage(ref Message m)
  72.             {
  73.                 if (m.Msg == (int)Win32.Msgs.WM_MOUSEMOVE)
  74.                     OnDragging();
  75.                 else if (m.Msg == (int)Win32.Msgs.WM_LBUTTONUP)
  76.                     EndDrag(false);
  77.                 else if (m.Msg == (int)Win32.Msgs.WM_CAPTURECHANGED)
  78.                     EndDrag(true);
  79.                 else if (m.Msg == (int)Win32.Msgs.WM_KEYDOWN && (int)m.WParam == (int)Keys.Escape)
  80.                     EndDrag(true);
  82.                 return OnPreFilterMessage(ref m);
  83.             }
  85.             protected virtual bool OnPreFilterMessage(ref Message m)
  86.             {
  87.                 return false;
  88.             }
  90.             protected sealed override void WndProc(ref Message m)
  91.             {
  92.                 if (m.Msg == (int)Win32.Msgs.WM_CANCELMODE || m.Msg == (int)Win32.Msgs.WM_CAPTURECHANGED)
  93.                     EndDrag(true);
  95.                 base.WndProc(ref m);
  96.             }
  97.         }
  99.         private abstract class DragHandler : DragHandlerBase
  100.         {
  101.             private DockPanel m_dockPanel;
  103.             protected DragHandler(DockPanel dockPanel)
  104.             {
  105.                 m_dockPanel = dockPanel;
  106.             }
  108.             public DockPanel DockPanel
  109.             {
  110.                 get { return m_dockPanel; }
  111.             }
  113.             private IDragSource m_dragSource;
  114.             protected IDragSource DragSource
  115.             {
  116.                 get { return m_dragSource; }
  117.                 set { m_dragSource = value; }
  118.             }
  120.             protected sealed override Control DragControl
  121.             {
  122.                 get { return DragSource == null ? null : DragSource.DragControl; }
  123.             }
  125.             protected sealed override bool OnPreFilterMessage(ref Message m)
  126.             {
  127.                 if ((m.Msg == (int)Win32.Msgs.WM_KEYDOWN || m.Msg == (int)Win32.Msgs.WM_KEYUP) &&
  128.                     ((int)m.WParam == (int)Keys.ControlKey || (int)m.WParam == (int)Keys.ShiftKey))
  129.                     OnDragging();
  131.                 return base.OnPreFilterMessage(ref m);
  132.             }
  133.         }
  134.     }
  135. }