将selectedItem从列表框绑定到不工作的属性ObservableCollection类型

Question

我试图在我的视图中使用selectedItem绑定属性（在我的视图模型中创建）。 我必须说列表框完全绑定到ObservableCollection并显示列表 但是当我尝试在messagebox上打印时，selectedItem我得到了空对象 这是我的ObservableCollection

ObservableCollection<Building> _buildingInstock = new ObservableCollection<Building>();

internal ObservableCollection<Building> BuildingInstock
{
    get { return _buildingInstock; }
    set
    {
        _buildingInstock = value;
        if(PropertyChanged!=null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs("BuildingInstock"));
        }
    }
}

这是xaml：

<ListBox x:Name="listview1" Grid.Row="11" 
    SelectedItem="{Binding Path=SelectedHouse,Mode=TwoWay}" 
    ItemTemplate="{StaticResource listboxtemplate}">

</ListBox>

在后面的视图代码中我有：

List_Of_Buildings temp=new List_Of_Buildings();
listview1.DataContext = temp.BuildingInstock;
listview1.ItemsSource = temp.BuildingInstock;

List_Of_Buildings类包含此属性：

Building _selectedHouse = new Building();

internal Building SelectedHouse
{
    get { return _selectedHouse; }
    set 
    {
        _selectedHouse = value;
        if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs("SelectedHouse"));
    }
}