BindingExpression 错误

Question

写ListView的时候不知道为何出现了BindingExpression错误，自己调试了很久也没有结果，也google了一下，发现stackoverflow里面有类似的回答，但是还是没解决，这个是为什么？

namespace Test {
	public ref class Message sealed {
	public:
		property Platform::String^ msg {Platform::String^ get() { return _msg; } void set(Platform::String^ t_msg) { _msg = t_msg; }}
	private:
		Platform::String^ _msg;
	};
}

MainPage::MainPage()
{
	using namespace Platform::Collections;
	InitializeComponent();
	
	itemSet = ref new Platform::Collections::Vector<Message^>;
	Message^ Message0 = ref new Message;
	Message0->msg = "Hello Message0";

	Message^ Message1 = ref new Message;
	Message1->msg = "Hello Message1";

	Message^ Message2 = ref new Message;
	Message2->msg = "Hello Message2";

	Message^ Message3 = ref new Message;
	Message3->msg = "Hello Message3";

	Message^ Message4 = ref new Message;
	Message4->msg = "Hello Message4";

	itemSet->Append(Message0);
	itemSet->Append(Message1);
	itemSet->Append(Message2);
	itemSet->Append(Message3);
	itemSet->Append(Message4);

	this->DataContext = itemSet;
	this->mylistView->ItemsSource = itemSet;
}

XAML：

        <ListView x:Name="mylistView" Margin="10,315,10,10" d:LayoutOverrides="LeftPosition, RightPosition, TopPosition, BottomPosition">
            <ListView.ItemTemplate>
                <DataTemplate>
                    <Grid Margin="6" Height="120">
                        <TextBlock Name="Test_Text" Margin="10,0,0,0" Text="{Binding msg}"></TextBlock>
                    </Grid>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>

错误信息如下：

Error: BindingExpression path error: 'msg' property not found on 'Test.Message'. BindingExpression: Path='msg' DataItem='Test.Message'; target element is 'Windows.UI.Xaml.Controls.TextBlock' (Name='Test_Text'); target property is 'Text' (type 'String')

用C++/CX写代码，但是我觉得应该问题不在语言，应该在XAML，但是实在是对XAML不够熟悉，有人可以解答一下吗？