wpf，DataTemplate不起作用

Question

我是WPF的新手，我有一个应用程序，我为自定义类型Person定义了一个datatemplate。 我在ContentControl中使用它，但我只看到我的类型Person的类型名称。 这是代码。

<Window x:Class="WpfTestApp.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
          xmlns:local="clr-namespace:WpfTestApp"
        Title="MainWindow" Height="350" Width="525">
    <Window.Resources>
        <DataTemplate DataType="local:Person" >
            <Grid>
                <Grid.RowDefinitions>
                    <RowDefinition Height="Auto"></RowDefinition>
                    <RowDefinition></RowDefinition>
                </Grid.RowDefinitions>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="200"></ColumnDefinition>
                    <ColumnDefinition></ColumnDefinition>
                </Grid.ColumnDefinitions>
                <Label Content="_Name:" Grid.Row="0" Grid.Column="0"></Label>
                <TextBox Text="{Binding Path=Name}" Grid.Column="1" Grid.Row="0"></TextBox>
                <Label Content="_Age:" Grid.Row="1" Grid.Column="0"></Label>
                <TextBox Text="{Binding Path=Age}" Grid.Column="1" Grid.Row="1"></TextBox>
            </Grid>
        </DataTemplate>
    </Window.Resources>
    <Grid >
        <ContentControl Content="{Binding }" >

        </ContentControl>
    </Grid>
</Window>

和....

public partial class MainWindow : Window
    {
        public Person _person {get;set;} 
        public MainWindow()
        {
            InitializeComponent();
            _person = new Person { Age = 30, Name = "David" };
            DataContext = _person;
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            MessageBox.Show("Button is clicked!!!");
        }
    }

    public class Person : INotifyPropertyChanged
    {
        private int _age;
        private string _name;
        public int Age
        {
            get
            {
                return _age;
            }
            set
            {
                if (value != _age)
                {
                    _age = value;
                    OnPropertyChanged("Age");
                }
            }
        }
        public string Name
        {
            get
            {
                return _name;
            }
            set
            {
                if (value != _name)
                {
                    _name = value;
                    OnPropertyChanged("Name");
                }
            }

        }

        public event PropertyChangedEventHandler PropertyChanged;

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