C# Xamarin.form-Masterdetailpage:System.Reflection.TargetInvocationException:调用的目标已引发异常

我使用xamarin.form便携式

使用MasterDetailPage时，我收到错误：“System.Reflection.TargetInvocationException:调用的目标已引发异常。”

下面是我的xaml代码

<?xml version="1.0" encoding="utf-8" ?>
<MasterDetailPage xmlns="http://xamarin.com/schemas/2014/forms"
         xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
         x:Class="SlideNavigation.Page1"
              IsPresented="True">
  <MasterDetailPage.Master>
<ContentPage>
  <ListView x:Name="listview" ItemSelected="Listview_itemSelected">
    <ListView.ItemTemplate>
      <DataTemplate>
        <TextCell Text="{Binding Name}" Detail="{Binding Status}"></TextCell>
      </DataTemplate>
    </ListView.ItemTemplate>
  </ListView>
</ContentPage>
</MasterDetailPage.Master>
<MasterDetailPage.Detail>
<ContentPage ></ContentPage>
</MasterDetailPage.Detail>
</MasterDetailPage>

下面是我的.cs代码

public partial class Page1 : MasterDetailPage
{
    public Page1()
    {
        InitializeComponent();

        listview.ItemsSource = new List<Contact>
       {
           new Contact { Name = "Kirti",Status = "True"},
           new Contact { Name = "Nilesh",Status = "False"}
       };
    }
    void Listview_itemSelected(object sender, SelectedItemChangedEventArgs e)
    {

        var contact = e.SelectedItem as Contact;
         Detail = new NavigationPage(new  Page2(contact.Name));
        IsPresented = false;
    }
}

公共部分类第1页：MasterDetailPage
{
公共页1（）
{
初始化组件（）；
listview.ItemsSource=新列表
{
新联系人{Name=“Kirti”，Status=“True”}，
新联系人{Name=“Nilesh”，Status=“False”}
};
}
void Listview_itemSelected（对象发送者，SelectedItemChangedEventArgs e）
{
var contact=e.选择editem作为联系人；
详细信息=新导航页面（新页面2（contact.Name））；
IsPresented=假；
}
}

请帮助我我犯了什么错误

---

提前感谢

您必须在母版页上设置Title属性

  <MasterDetailPage.Master>
    <ContentPage Title="Content Page">
      <ContentPage.Content>
        <ListView x:Name="listview" ItemSelected="Listview_itemSelected">
          <ListView.ItemTemplate>
            <DataTemplate>
              <TextCell Text="{Binding Name}" Detail="{Binding Status}"></TextCell>
            </DataTemplate>
          </ListView.ItemTemplate>
        </ListView>
      </ContentPage.Content>
    </ContentPage>
  </MasterDetailPage.Master>

---

必须在母版页上设置标题属性

  <MasterDetailPage.Master>
    <ContentPage Title="Content Page">
      <ContentPage.Content>
        <ListView x:Name="listview" ItemSelected="Listview_itemSelected">
          <ListView.ItemTemplate>
            <DataTemplate>
              <TextCell Text="{Binding Name}" Detail="{Binding Status}"></TextCell>
            </DataTemplate>
          </ListView.ItemTemplate>
        </ListView>
      </ContentPage.Content>
    </ContentPage>
  </MasterDetailPage.Master>