橡皮区矩形 CRectTracker C# 实现

本文要求读者熟悉 C#

开发环境： Visual Studio .NET 2003 Windows 2000

测试环境：Windows 2000

更新记录：2004.4.7 第一次更新

使用许可：代码是否免费使用

功能介绍：
　　在MFC中CRectTracker是一个很有用的类，可最近学习C#时，发现没有，于是就从MFC转换了一个供大家享用。



使用该类比较简单，几乎和 MFC中 的 CRectTracker 一样，在MDI中：

public class CReportDoc 
{ ...
public CRectTracker m_tracker=null; 

 public CReportDoc(MainWindow mainWin) 
 {  ...
  m_tracker=new CRectTracker(); 
  m_tracker.m_rect.X = 10; 
  m_tracker.m_rect.Y = 10;
  m_tracker.m_rect.Width = 91;
  m_tracker.m_rect.Height = 91; 
  ...
 }
 ...
}      

相应的在VIEW类里面

public class CReportView : System.Windows.Forms.Form 
{
     ...
     private void InitializeComponent() 
     { 
 ...
 this.MouseDown += 
 new System.Windows.Forms.MouseEventHandler(this.CReportView_MouseDown); 
 this.Paint += 
 new System.Windows.Forms.PaintEventHandler(this.PaintHandler); 

 // 因为C#中不支持OnSetCursor所以只好用MouseMove替代了，
 // 各位兄台还有更好的方法，请告之
 this.MouseMove+=new MouseEventHandler(CReportView_MouseMove); 
     }

     private void PaintHandler(Object sender, PaintEventArgs e) 
     {
 Graphics gs=e.Graphics; 

 //其余的画图代码
 myDoc.m_tracker.OnDraw(gs); 
     }
     private void CReportView_MouseDown(object sender, 
                                   MouseEventArgs e) 
     {
     if(e.Button==MouseButtons .Left) 
     {
 Rectangle rectSave=new Rectangle(); 
 Point pt=new Point(e.X,e.Y);
 myDoc.m_tracker.GetTrueRect(ref rectSave);
 if (myDoc.m_tracker.HitTest(pt) < 0) 
 { // just to demonstrate CRectTracker::TrackRubberBand 
  CRectTracker tracker=new CRectTracker();
  if (tracker.TrackRubberBand(this, 
                              pt, 
     myDoc.m_bAllowInvert))
  {   // see if rubber band intersects with the doc''s tracker 
   tracker.NormalizeRect(ref tracker.m_rect);
   // so intersect rect works
   if (tracker.m_rect.IntersectsWith(myDoc.m_tracker.m_rect))
   {  // if so, put resize handles on it (ie. select it) 
    if ((myDoc.m_tracker.m_nStyle &
      CRectTracker.StyleFlags.resizeInside)!=0) 
    {   // swap from resize inside to 
     // resize outside for effect
     myDoc.m_tracker.m_nStyle &= 
     ~CRectTracker.StyleFlags.resizeInside; 
     myDoc.m_tracker.m_nStyle |= 
     CRectTracker.StyleFlags.resizeOutside;
    } 
    else 
    {// just use inside resize handles on first time 
     myDoc.m_tracker.m_nStyle &= 
      ~CRectTracker.StyleFlags.resizeOutside; 
     myDoc.m_tracker.m_nStyle |= 
       CRectTracker.StyleFlags.resizeInside; 
    } 
   }
  }
  myDoc.UpdateAllViews(null); 
      } 
 } 
 else 
 {
     if (myDoc.m_tracker.Track(this, 
   pt, 
           myDoc.m_bAllowInvert,null)) 
     {   
  // normal tracking action, when tracker is "hit"
  myDoc.UpdateAllViews(null);
     }
 }
     }

     private void CReportView_MouseMove(object sender, MouseEventArgs e)
     {
 Point mousept=new Point(e.X,e.Y); 
 if(!myDoc.m_tracker.SetCursor(this,0,mousept)) 
 this.Cursor=Cursors.Arrow;
     }
     ...
}

结束。