WPF ComboBox + MVVM，项目选择提示

在研究项目的过程中，在选择要发出请求的元素时，有必要制作组合，例如 - “您确定吗？”，如果没有，请返回旧值。问题是我做错了什么？框架工作 4.0。提前致谢。

现在我得到了以下信息：

<x:Array x:Key="UnitArray" Type="sys:UInt32" 
   xmlns:sys="clr-namespace:System;assembly=mscorlib">
     <sys:UInt32>0x0</sys:UInt32>
     <sys:UInt32>0xFFFFFFFF</sys:UInt32>
</x:Array>

<DataTemplate x:Key="ComboboxOfUnit" >
<StackPanel Orientation="Horizontal">                   
    <TextBlock  VerticalAlignment="Center" >
        <TextBlock.Style>
            <Style TargetType="TextBlock">
                <Style.Triggers>
                    <DataTrigger Binding="{Binding}" Value="0x0">
                        <Setter Property="Text" Value="value1"/>
                    </DataTrigger>
                    <DataTrigger Binding="{Binding}" Value="0xFFFFFFFF">
                        <Setter Property="Text" Value="value2"/>
                    </DataTrigger>
                </Style.Triggers>
            </Style>
        </TextBlock.Style>
    </TextBlock>
</StackPanel>
</DataTemplate>

在资源块和

<ComboBox ItemsSource="{StaticResource ResourceKey=UnitArray}" 
      SelectedItem="{Binding UnitOf}" 
      ItemTemplate="{StaticResource ComboboxOfUnit}"/>

在模型中的 xaml 代码的主体中，我们有以下内容

uint _prev_UnitOf;
public uint PrevUnitOf
{
    get { return _prev_UnitOf; }
    set
    {
        _prev_UnitOf = value;

        if (!_prev_UnitOf.Equals(_UnitOf))
        {
           // HasHasChangedArray[_UnitOf_] = true;
            //bfUnitOf = true;
            /HasChanged = true;
        }
        else
        {
            //HasHasChangedArray[_UnitOf_] = false;
            //bfUnitOf = false;
            //HasChanged = isChangedArray();
        }
        OnPropertyChanged(() => PrevUnitOf);
    }
}

uint _UnitOf;
public uint UnitOf
{
    get { return _UnitOf; }
    set
    {

        if (!_UnitOf.Equals(value))
            if (AppContext.Instance.ErrorReportMSG("Вы уверены?", "", Common.Interfaces.MsgType.Question))
            {
                _UnitOf = value;
                if (!_prev_UnitOf.Equals(_UnitOf))
                {

                    //HasHasChangedArray[_UnitOf_] = true;
                    //bfUnitOf = true;
                    //HasChanged = true;
                }
                else
                {
                    //HasHasChangedArray[_UnitOf_] = false;
                    //bfUnitOf = false;
                    //HasChanged = isChangedArray();
                }
            }
            else
            {
                _UnitOf = _prev_UnitOf;
                //bfUnitOf = false;
                //HasChanged = isChangedArray();
            }
        OnPropertyChanged(() => UnitOf);
    }
} 

其中AppContext.Instance.ErrorReportMSG("Вы уверены?", "", Common.Interfaces.MsgType.Question)消息框和 OnPropertyChanged(() => UnitOf) 的包装器

public void OnPropertyChanged(string propertyName)
{
    if (PropertyChanged != null)
        PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}

/// <summary>
/// Метод генерации события изменения свойства объекта
/// </summary>
/// <typeparam name="T">Тип объекта</typeparam>
/// <param name="action">Лямбда функция доступа свойству</param>
protected void OnPropertyChanged<T>(Expression<Func<T>> action)
{
    var propertyName = GetPropertyName(action);
    OnPropertyChanged(propertyName);
}

/// <summary>
/// Метод получения имени параметра
/// </summary>
/// <typeparam name="T">Тип объекта</typeparam>
/// <param name="action">Лямбда функция доступа свойству</param>
/// <returns>Возвращает имя параметра</returns>
private static string GetPropertyName<T>(Expression<Func<T>> action)
{
    var expression = (MemberExpression)action.Body;
    var propertyName = expression.Member.Name;
    return propertyName;
}