C# 将处理程序添加到FrameworkElementFactory组合框-类型错误？

在阅读了许多关于这个显然令人烦恼的问题的答案之后，包括这篇似乎指明了方向的优秀回复：，在尝试了几天在这个网站上阅读的各种不同建议之后，我仍然无法在我的设置中实现这一点

因此，基础数据结构的公共成员是：

    #region Public Members
    public EMSBasicDevice Device    { get => _Device;           set => _Device = value; }
    public BitmapImage DeviceIcon   { get => _DeviceIcon;       set => _DeviceIcon = value; }
    public string DeviceIconPath    { get => _DeviceIconPath;   set => _DeviceIconPath = value; }
    public int RowHeight            { get => _RowHeight;        set => _RowHeight = value; }
    public Color RowColour          { get => _RowColour;        set => _RowColour = value; }
    public string DataDescription   { get => _DataDescription;  set => _DataDescription = value; }
    public string ZoneText          { get => _Zone;             set => _Zone = value; }
    public string LocationText      { get => _LocationText;     set => _LocationText = value; }
    public bool IsHeader            { get => _IsHeader;         set => _IsHeader = value; }
    public InputOutput IOType       { get => _IOType;           set => _IOType = value; }
    public CellControl ShowCombo    { get => _ShowCombo;        set => _ShowCombo = value; }
    public int IOPoint              { get => _IOPoint;          set => _IOPoint = value; }
    public int IOIndex              { get => _IOIndex;          set => _IOIndex = value; }
    public int RowNumber            { get => _RowNumber;        set => _RowNumber = value; }
    public Visibility SensorVis     { get => _SensorVis;        set => _SensorVis = value; }
    public IEnumerable ItemsSource  { get => _ItemsSource;      set => _ItemsSource = value; }
    public object SelectedItem      { get => _SelectedItem;     set => _SelectedItem = value; }

    public SelectionChangedEventHandler OnChange;
    #endregion

目标UI元素是DataGrid。所有列都在代码中显式创建。下面是第4列的代码，其中包含一个组合框。为选项列表（ItemsSource）、所选项、是否显示控件（不是在网格的每一行）和（尝试）传递对“更改处理程序”的引用提供绑定。Factory元素组合框没有更改处理程序的DP。因此，我的代码如下所示，遵循上面链接中给出的信息：

        // Fourth Column: Sensor Settings
        DataGridTemplateColumn SensorSettingCol = new DataGridTemplateColumn();
           
        Binding SensorChoicesBind = new Binding("ItemsSource")
        {
            Mode = BindingMode.TwoWay,
            UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged,
        };
        Binding SensorSettingBind = new Binding("SelectedItem")
        {
            Mode                  = BindingMode.TwoWay,
            UpdateSourceTrigger   = UpdateSourceTrigger.PropertyChanged,
            NotifyOnSourceUpdated = true
        };
        Binding SensorVisibility = new Binding("SensorVis")
        {
            Mode = BindingMode.TwoWay,
            UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged
        };
        Binding OnChangeBinding = new Binding("OnChange")
        {
            Mode = BindingMode.TwoWay,
            UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged
        };
        FrameworkElementFactory cbInstance1 = new FrameworkElementFactory(typeof(ComboBox));
        ImageTemplate = new DataTemplate();
        SensorSettingCol.CellTemplate = ImageTemplate;
        SensorSettingCol.Width        = new DataGridLength(150);
        SensorSettingCol.CanUserSort  = false;
        ImageTemplate.VisualTree = cbInstance1;

        cbInstance1.SetBinding(ComboBox.ItemsSourceProperty,    SensorChoicesBind);
        cbInstance1.SetBinding(ComboBox.SelectedValueProperty,  SensorSettingBind);
        cbInstance1.SetBinding(ComboBox.VisibilityProperty,     SensorVisibility);
        
        cbInstance1.AddHandler(ComboBox.SelectionChangedEvent, new RoutedPropertyChangedEventHandler<object>(SelectionChanged));

        TheDataGrid.Columns.Add(SensorSettingCol);


The handler looks like this:

        public void SelectionChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
        {
            //do stuff with e.OriginalSource
        }


Of course, this is only half the problem - the real issue is accessing the actual handler in the dataset
which should be called when the user selects a different choice in the ComboBox. Note that the
implementation is intended to be as generic as possible - the combo boxes on different rows access
different choices based upon the underlying dataset.

The error message is:

        System.ArgumentException
          HResult=0x80070057
          Message=Handler type is not valid.
          Source=PresentationFramework
          StackTrace:
           at System.Windows.FrameworkElementFactory.AddHandler(RoutedEvent routedEvent, Delegate handler, Boolean handledEventsToo)
           at System.Windows.FrameworkElementFactory.AddHandler(RoutedEvent routedEvent, Delegate handler)
           at EMS_Config_Tool.UIComponents.WPF.DeviceEditControl.SetupDeviceGrid(DataGrid TheDataGrid) in C:\Workspace\90504_SmartCellConfigTool\Trunk\EMS Config Tool\UIComponents\WPF\DeviceEditControl.xaml.cs:line 794

The question is: The handler type is wrong, so what should the type actually be? 
And for a Gold Star, is there a MUCH BETTER way to link the SelectionChanged event 
to the appropriate handler?

//第四列：传感器设置
DataGridTemplateColumn SensorSettingCol=新DataGridTemplateColumn（）；
Binding SensorChoicesBind=新绑定（“ItemsSource”）
{
Mode=BindingMode.TwoWay，
UpdateSourceTrigger=UpdateSourceTrigger.PropertyChanged，
};
绑定传感器设置绑定=新绑定（“SelectedItem”）
{
Mode=BindingMode.TwoWay，
UpdateSourceTrigger=UpdateSourceTrigger.PropertyChanged，
NotifyOnSourceUpdated=true
};
绑定SensorVisibility=新绑定（“SensorVis”）
{
Mode=BindingMode.TwoWay，
UpdateSourceTrigger=UpdateSourceTrigger.PropertyChanged
};
Binding OnChangeBinding=新绑定（“OnChange”）
{
Mode=BindingMode.TwoWay，
UpdateSourceTrigger=UpdateSourceTrigger.PropertyChanged
};
FrameworkElementFactory cbInstance1=新FrameworkElementFactory（类型（组合框））；
ImageTemplate=新数据模板（）；
SensorSettingCol.CellTemplate=图像模板；
SensorSettingCol.Width=新数据网格长度（150）；
SensorSettingCol.CanUserSort=false；
ImageTemplate.VisualTree=cbInstance1；
cbInstance1.SetBinding（ComboBox.ItemsSourceProperty，SensorChoicesBind）；
cbInstance1.SetBinding（ComboBox.SelectedValueProperty，SensorSettingBind）；
cbInstance1.SetBinding（ComboBox.VisibilityProperty，传感器可见性）；
cbInstance1.AddHandler（ComboBox.SelectionChangedEvent，新RoutedPropertyChangedEventHandler（SelectionChanged））；
DataGrid.Columns.Add（传感器设置列）；
处理程序如下所示：
public void SelectionChanged（对象发送方，RoutedPropertyChangedEventArgs e）
{
//用e.OriginalSource做一些事情
}
当然，这只是问题的一半——真正的问题是访问数据集中的实际处理程序
当用户在组合框中选择其他选项时，应调用该选项。请注意
实现的目的是尽可能通用-不同行上的组合框访问
基于基础数据集的不同选择。
错误消息是：
System.ArgumentException
HResult=0x80070057
消息=处理程序类型无效。
Source=PresentationFramework
堆栈跟踪：
在System.Windows.FrameworkElementFactory.AddHandler（RoutedEvent RoutedEvent、委托处理程序、布尔HandleEventsToo）
位于System.Windows.FrameworkElementFactory.AddHandler（RoutedEvent RoutedEvent，委托处理程序）
在C:\Workspace\90504\u SmartCellConfigTool\Trunk\EMS Config Tool\UIComponents\WPF\DeviceEditControl.SetupDeviceGrid（数据网格）中的EMS\u Config\u Tool.UIComponents.WPF.DeviceEditControl.SetupDeviceGrid（数据网格）：第794行
问题是：处理程序类型是错误的，那么该类型实际上应该是什么？
对于一个金星来说，有没有更好的方式来链接SelectionChanged事件
给合适的处理者？