WPF DataGrid System.NullReferenceException

Question

我需要WPF DataGrid中的一些额外功能，所以我继承它。

我的代码如下所示

 public class GenericDataGrid : DataGrid
 { 
    public GenericDataGrid()
    {
       PreviewMouseMove += GenericDataGrid_PreviewMouseMove;
    } 
    private void GenericDataGrid_PreviewMouseMove(object sender, MouseEventArgs e)
    {
        if(e == null)
        {
          Log.Error(this, error);
        }
        else
        {...}
    }
}

使用此代码，在我点击网格的随机时间，我收到以下错误：

***System.RuntimeType - System.NullReferenceException: Object reference not set to an instance of an object.
   at LBG.PT.Common.View.Core.Controls.Grid.GenericDataGrid.GenericDataGrid_PreviewMouseMove(Object sender, MouseEventArgs e) in c:\BuildAgent2\work\fbe7560eaf130ae\Common\Grid\GenericDataGrid.cs:line 235
   at System.Windows.Input.MouseEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
   at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
   at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
   at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   at System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)
   at System.Windows.UIElement.RaiseEvent(RoutedEventArgs args, Boolean trusted)
   at System.Windows.Input.InputManager.ProcessStagingArea()
   at System.Windows.Input.InputManager.ProcessInput(InputEventArgs input)
   at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
   at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)
   at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)***

任何想法，这是否意味着它是控件本身的Bug？如果是这样，我该如何解决这个问题？