ZedGraph5.1.5源码分析去掉鼠标悬浮内容闪烁问题(附源码下载)

￡神魔★判官ぃ 2023-10-08 11:39 13阅读 0赞

## 场景 ##

在使用ZedGraph绘制曲线图时，将鼠标悬浮时内容闪烁，且频率很高。

![20200107103502447.gif][]

找到其源码，发现不论鼠标移动的范围大小，甚至乎不论鼠标是否移动，都要刷新一次Tooltip。

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## 实现 ##

首先来到ZedGraph的官网

[https://sourceforge.net/projects/zedgraph/][https_sourceforge.net_projects_zedgraph]

然后点击File下的zedgraph source

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk_size_16_color_FFFFFF_t_70][]

选择对应版本，这里是5.1.5

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk_size_16_color_FFFFFF_t_70 1][]

下载成功后，将zip解压

找到source下的工程文件，双击使用VS打开

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk_size_16_color_FFFFFF_t_70 2][]

然后找到ZedGraphControl.Events.cs

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk_size_16_color_FFFFFF_t_70 3][]

找到其ZedGraphControl\_MouseMove方法此方法是鼠标移动时的事件处理

可以看到其对两个方法的处理，一个是HandlePointValues，这是对显示线上的点的坐标时的处理，一个是HandleCursorValues这是对获取最近曲线上的点的坐标时的处理。

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk_size_16_color_FFFFFF_t_70 4][]

这样看你的ZedGraph是开启的哪样设置。

假如是设置经过线上点时才显示

zgc.IsShowPointValues = true;

那么就要修改

HandlePointValues( mousePt );

这个方法

首先声明一个类变量

private object lastObj;

用来存储上一次使用的对象，然后找到其判断条件，添加当前是否与上一次是同一对象

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk_size_16_color_FFFFFF_t_70 5][]

然后在最后方法返回时将当前对象赋值给上一次对象。

lastObj = nearestObj;

完整参考代码

private Point HandlePointValues( Point mousePt )
      {
       int iPt;
       GraphPane pane;
       object nearestObj;
    
       using ( Graphics g = this.CreateGraphics() )
       {
    
        if ( _masterPane.FindNearestPaneObject( mousePt,
         g, out pane, out nearestObj, out iPt ) )
        {
                        if (nearestObj is CurveItem && iPt >= 0 && !object.Equals(nearestObj, lastObj))
         {
          CurveItem curve = (CurveItem)nearestObj;
          // Provide Callback for User to customize the tooltips
          if ( this.PointValueEvent != null )
          {
           string label = this.PointValueEvent( this, pane, curve, iPt );
           if ( label != null && label.Length > 0 )
           {
            this.pointToolTip.SetToolTip( this, label );
            this.pointToolTip.Active = true;
           }
           else
            this.pointToolTip.Active = false;
          }
          else
          {
    
           if ( curve is PieItem )
           {
            this.pointToolTip.SetToolTip( this,
             ( (PieItem)curve ).Value.ToString( _pointValueFormat ) );
           }
           //       else if ( curve is OHLCBarItem || curve is JapaneseCandleStickItem )
           //       {
           //        StockPt spt = (StockPt)curve.Points[iPt];
           //        this.pointToolTip.SetToolTip( this, ( (XDate) spt.Date ).ToString( "MM/dd/yyyy" ) + "\nOpen: $" +
           //        spt.Open.ToString( "N2" ) +
           //        "\nHigh: $" +
           //        spt.High.ToString( "N2" ) + "\nLow: $" +
           //        spt.Low.ToString( "N2" ) + "\nClose: $" +
           //        spt.Close.ToString
           //        ( "N2" ) );
           //       }
           else
           {
            PointPair pt = curve.Points[iPt];
    
            if ( pt.Tag is string )
             this.pointToolTip.SetToolTip( this, (string)pt.Tag );
            else
            {
             double xVal, yVal, lowVal;
             ValueHandler valueHandler = new ValueHandler( pane, false );
             if ( ( curve is BarItem || curve is ErrorBarItem || curve is HiLowBarItem )
               && pane.BarSettings.Base != BarBase.X )
              valueHandler.GetValues( curve, iPt, out yVal, out lowVal, out xVal );
             else
              valueHandler.GetValues( curve, iPt, out xVal, out lowVal, out yVal );
    
             string xStr = MakeValueLabel( curve.GetXAxis( pane ), xVal, iPt,
              curve.IsOverrideOrdinal );
             string yStr = MakeValueLabel( curve.GetYAxis( pane ), yVal, iPt,
              curve.IsOverrideOrdinal );
    
             this.pointToolTip.SetToolTip( this, "( " + xStr + ", " + yStr + " )" );
    
             //this.pointToolTip.SetToolTip( this,
             // curve.Points[iPt].ToString( this.pointValueFormat ) );
            }
           }
    
           this.pointToolTip.Active = true;
          }
         }
         else
          this.pointToolTip.Active = false;
        }
        else
         this.pointToolTip.Active = false;
    
        //g.Dispose();
       }
                lastObj = nearestObj;
       return mousePt;
      }

具体其他优化与功能修改可自行发掘。

如果在ZedGraph中设置的是显示最近曲线上的点的坐标，即

zgc.IsShowCursorValues = true;

那么就要修改源码的HandleCursorValues方法

同样声明一个类变量存储上次获得的点

private Point lastMovedPoint;

然后在方法中加上判断并通过

this.pointToolTip.AutomaticDelay = 1000;

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk_size_16_color_FFFFFF_t_70 6][]

设置提示延迟1秒。最后再将当前点赋值给类变量。

lastMovedPoint = mousePt;

完整示例代码

private Point HandleCursorValues( Point mousePt )
      {
                GraphPane pane = _masterPane.FindPane(mousePt);
                if (pane != null && pane.Chart._rect.Contains(mousePt) && !mousePt.Equals(lastMovedPoint))
                {
                    // Provide Callback for User to customize the tooltips
                    if (this.CursorValueEvent != null)
                    {
                        string label = this.CursorValueEvent(this, pane, mousePt);
                        if (label != null && label.Length > 0)
                        {
                            this.pointToolTip.AutomaticDelay = 1000;
                            this.pointToolTip.SetToolTip(this, label);
                            this.pointToolTip.Active = true;
                        }
                        else
                        {
                            this.pointToolTip.Active = false;
                        }
                        lastMovedPoint = mousePt;
                    }
                    else
                    {
                        double x, x2, y, y2;
                        pane.ReverseTransform(mousePt, out x, out x2, out y, out y2);
                        string xStr = MakeValueLabel(pane.XAxis, x, -1, true);
                        string yStr = MakeValueLabel(pane.YAxis, y, -1, true);
                        string y2Str = MakeValueLabel(pane.Y2Axis, y2, -1, true);
                        this.pointToolTip.AutomaticDelay = 1000;
                        this.pointToolTip.SetToolTip(this, "( " + xStr + ", " + yStr + ", " + y2Str + " )");
                        this.pointToolTip.Active = true;
                    }
                  
                }
                else
                    this.pointToolTip.Active = false;
    
                return mousePt;
              
      }

注：

这里只着重修改当用户重写此事件的情况下，即this.CursorValueEvent != null时，具体情况可跟据自己需要进行修改。

### ZedGraph5.1.5源码与修改版源码下载 ###

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[20200107103502447.gif]: https://img-blog.csdnimg.cn/20200107103502447.gif
[https_blog.csdn.net_badao_liumang_qizhi]: https://blog.csdn.net/badao_liumang_qizhi
[https_sourceforge.net_projects_zedgraph]: https://sourceforge.net/projects/zedgraph/
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20200107103512963.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk=,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/2020010710351142.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk=,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/20200107111044689.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk=,size_16,color_FFFFFF,t_70
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