模型无效时，不会捕获Oxyplot的鼠标事件

2 回答

• 0

  我发现InvalidatePlot导致了PlotView从未捕获到鼠标按钮事件（如OnMouseDown（MouseButtonEventArgs e））的问题 . 为了解决这个问题，我使用了另一个WPF对象来捕获鼠标事件并强制调用我的PlotView的鼠标处理方法：

  1）我在另一个ZIndex级别添加了一个WPF网格 . 并附加到鼠标事件（MouseDown，MouseWheel等）的函数：

  <Grid x:Name="Grid_MouseCatcher"
          HorizontalAlignment="Stretch"
          VerticalAlignment="Stretch"
          Panel.ZIndex="2"
          MouseDown="Grid_MouseCatcher_MouseDown"
          MouseEnter="Grid_MouseCatcher_MouseEnter"
          MouseLeave="Grid_MouseCatcher_MouseLeave"
          MouseMove="Grid_MouseCatcher_MouseMove"
          MouseUp="Grid_MouseCatcher_MouseUp"
          MouseWheel="Grid_MouseCatcher_MouseWheel"
          Opacity="0.0"
          PreviewMouseMove="SetFocusToOxyPlot" />
  <oxy:PlotView x:Name="PlotView"
          HorizontalContentAlignment="Stretch"
          VerticalContentAlignment="Stretch"
          Panel.ZIndex="1"
          Model="{Binding PlotModel}" />
  

  2）网格处理的每个事件都会调用我在OxyPlot源代码中创建的公共方法：

  /// <summary>
   /// Sends mouse events from the overlaying grid to the PlotView. Forcing an Action.
   /// This was included due to an OxyPlot bug where the OnMouse... methods were not being called 
   /// when the plot was invalidated via InvalidatePlot(...)
   /// </summary>
   /// <param name="sender"></param>
   /// <param name="e"></param>
   private void Grid_MouseCatcher_MouseDown(object sender, MouseButtonEventArgs e)
   {
       Debug.WriteLine("MouseCatcher - Down: " + e.GetPosition(Grid_MouseCatcher).X + " " + e.GetPosition(Grid_MouseCatcher).Y);
       PlotView.ForceMouseDown(e);
   }
  

  3）在源代码文件OxyPlot.Wpf \ PlotBase.Events.cs我创建功能（如ForceMouseDown（MouseButtonEventArgs E）），其明确要求保护的鼠标事件（onmousedown事件（MouseButtonEventArgs e））的

  /// <summary>
  /// Forces a call to Mouse handler. 
  /// This was needed because the events were getting lost when the model was updating
  /// </summary>
  /// <param name="e"></param>
  /// <returns></returns>
  public void ForceMouseDown(MouseButtonEventArgs e){
      this.OnMouseDown(e);
  }
  
  
  /// <summary>
  /// Invoked when an unhandled MouseDown attached event reaches an element in its route that is derived from this class. 
  /// Implement this method to add class handling for this event.
  /// </summary>
  /// <param name="e">The <see cref="T:System.Windows.Input.MouseButtonEventArgs" /> that contains the event data. 
  /// This event data reports details about the mouse button that was pressed and the handled state.</param>
  protected override void OnMouseDown(MouseButtonEventArgs e)
  {
      base.OnMouseDown(e);
      if (e.Handled)
      {
          return;
      }
  
      this.Focus();
      this.CaptureMouse();
  
      // store the mouse down point, check it when mouse button is released to determine if the context menu should be shown
      this.mouseDownPoint = e.GetPosition(this).ToScreenPoint();
  
      e.Handled = this.ActualController.HandleMouseDown(this, e.ToMouseDownEventArgs(this));
  }
  

  通过这种方式修复问题，我仍然可以按照OxyPlot建议的方式将鼠标事件处理程序添加到我的Plotview中，因为它们的OnMouse ####事件仍然被调用，它们现在只是由覆盖网格显式调用 .

  回复于 2024-04-28T21:28:40+08:00
• 0

  基于CodyF的修复，我发现了一个更简单的修复方法 . 在OxyPlot.Wpf.PlotBase中的OnApplyTemplate（）末尾添加以下行：

  var mouseGrid = new Grid();
  mouseGrid.Background = Brushes.Transparent; // background must be set for hit test to work
  this.grid.Children.Add(mouseGrid);
  

  但是，这种变化目前会制动工具提示 . 另请参阅OxyPlot的github页面中的pull request .

  回复于 2024-04-28T21:28:40+08:00