关于c＃：BindingProxy：绑定到索引属性

我有一个BindingProxy将DataGrid的DataGridColumns的可视性-属性绑定到字典中的值(" ColumnsVisibility")。我也有一个上下文菜单，它应该可以隐藏/显示网格的列。

如果在InitializeComponent()之前用信息填充了字典" ColumnsVisibility"，则将应用初始设置，即应用了我将DictionaryEntry设置为的值。

我的目标是选中上下文菜单中的复选框，然后列会出现/消失。因为ContextMenu和Columns不是与DataGrid或其他所有对象相同的可视树的成员，所以我使用的是Proxy。
我的问题是，在ContextMenu中选中/取消选中CheckBox不会更改ColumnsVisibility [ElementName]的值。如果将check / uncheck-Event添加到Checkbox，则可以在代码中使用它来更改它，但是触发PropertyChanged-Event不会改变任何视觉效果。该列保持原样。

indingProxy是否将事件转发到GUI，反之亦然？目前看来还没有。
任何人都有一个想法如何解决这个问题？

编辑：
BindingProxy：

public class BindingProxy : Freezable
{
    #region Overrides of Freezable

    protected override Freezable CreateInstanceCore()
    {
        return new BindingProxy();
    }

    #endregion

    public object Data
    {
        get { return (object)GetValue(DataProperty); }
        set { SetValue(DataProperty, value); }
    }

    // Using a DependencyProperty as the backing store for Data.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty DataProperty =
        DependencyProperty.Register("Data", typeof(object), typeof(BindingProxy), new UIPropertyMetadata(null));
}

编辑2：
ColumnsVisibilty属性

private Dictionary _ColumnsVisibility = new Dictionary();
public Dictionary ColumnsVisibility
    {
        get{return(_ColumnsVisibility);}
        set
        {  
            _ColumnsVisibility = value;

            if (PropertyChanged != null)
                PropertyChanged(null, new PropertyChangedEventArgs("ColumnsVisibility"));
        }
    }

在InitializeComponent()之前，这是在加载时完成的：

1	_ColumnsVisibility.Add("ElementName", false);

编辑3
好的，这是完整的源代码：
互动逻辑：

using System.Collections.Generic;
using System.Security;
using System.Windows;
using System.Windows.Controls;
using System.Collections.ObjectModel;
using System.ComponentModel;

namespace HyperV
{
/// 

/// Interaction logic for HyperVControl.xaml
/// 
public partial class HyperVControl : UserControl, INotifyPropertyChanged
{
    public HyperVControl()
    {            
        #region Set default visibility for Columns
        _ColumnsVisibility.Add("ElementName", false);
        //(...)
        #endregion

        InitializeComponent();
    }

    #region Control triggered
    private void UserControl_Loaded(object sender, RoutedEventArgs e)
    {

    }

    /// 

    /// Is Triggered by Checkboxes, that are in the contextmenu of the DataGrid-Header to show/hide columns
    /// 
    /// The Checkbox, that send this command
    /// 
    private void CheckBox_Checked(object sender, RoutedEventArgs e)
    {
        //This sets the value in ColumnsVisibility to be sure. The value is NOT set by binding (but should...)
        ColumnsVisibility[((CheckBox)sender).Tag.ToString()] = (bool)((CheckBox)sender).IsChecked;

        //Nothing of this works
        if (PropertyChanged != null)
        {
            PropertyChanged(null, new PropertyChangedEventArgs("ColumnsVisibility"));
            PropertyChanged(null, new PropertyChangedEventArgs("ColumnsVisibility[Machinename]"));
            PropertyChanged(null, new PropertyChangedEventArgs("Data.ColumnsVisibility"));
            PropertyChanged(null, new PropertyChangedEventArgs("Data.ColumnsVisibility[Machinename]"));
        }
    }
    #endregion

    #region Properties (private and publics)      
    private ObservableCollection _HVMachineList;      
    private Dictionary _ColumnsVisibility = new Dictionary();

    /// 

    /// Contains all loaded information about the virtual Clients
    /// 
    public ObservableCollection HVMachineList
    {
        get { return _HVMachineList; }
        set
        {
            _HVMachineList = value;

            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs("HVMachineList"));
        }
    }

    /// 

    /// To set
    /// 
    public Dictionary ColumnsVisibility
    {
        get{return(_ColumnsVisibility);}
        set
        {  
            _ColumnsVisibility = value;

            if (PropertyChanged != null)
                PropertyChanged(null, new PropertyChangedEventArgs("ColumnsVisibility"));
        }
    }
    #endregion

    #region Events
    //To Update Content on the Form
    public event PropertyChangedEventHandler PropertyChanged;        
    #endregion
}

//Binding Proxy
#region Freezable for Context-Menu-Data-Transmition
public class BindingProxy : Freezable
{
    #region Overrides of Freezable

    protected override Freezable CreateInstanceCore()
    {
        return new BindingProxy();
    }

    #endregion

    public object Data
    {
        get { return (object)GetValue(DataProperty); }
        set { SetValue(DataProperty, value); }
    }

    // Using a DependencyProperty as the backing store for Data.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty DataProperty =
        DependencyProperty.Register("Data", typeof(object), typeof(BindingProxy), new UIPropertyMetadata(null));
}
#endregion
}