C# Xamarin ContentView构造函数

我正在创建ContentView的一个子类，

UserPostView

，用作ListView中的数据模板。我通过创建

UserPostView

的新实例，动态地将项目添加到ListView的ItemSource中

<Image x:Name="PictureView" Source="Logo" BackgroundColor="#ddd" />
<Label x:Name="NameView" Text="Name" TextColor="#444" FontAttributes="Bold" Grid.Row="0" Grid.Column="1" Margin="10" />
<Label x:Name="LocationNameView" Text="Location" TextColor="#666" Grid.Row="0" Grid.Column="2" YAlign="Center" />
<Label x:Name="DeptNameView" Text="Dept" TextColor="#666" Grid.Row="0" Grid.Column="3" YAlign="Center" />

但是当我在ListView中使用它时，它不会显示传递的数据，而是显示原始数据。（Text=“Name”…）

---

救命啊！如何让它们显示通过构造函数传递的数据

如果您能提供ListView的xaml和DataTemplate，我们可以为您提供更好的答案

但是，我猜ListView的

项资源应设置为
ViewModel:INotifyPropertyChanged
列表，其中包含您的属性，而不是您的ContentView，并且您的ContentView应绑定到该ViewModel。例如：

public partial class UserPostView : ContentView
{
    public UserPostView()
    {
        InitializeComponent();
    }
}

//NOTE: in UserPostView.xaml 
<Image Source="{Binding Picture}" BackgroundColor="#ddd" />
<Label Text="{Binding PostOwner}" TextColor="#444" FontAttributes="Bold" Margin="10" />
<Label Text="{Binding PostOwnerLocation}" TextColor="#666" YAlign="Center" />
...

在您的页面中：

public TimelinePage()
{
    InitializeComponent();
    ImageSource pic = ImageSource.FromUri(new Uri("https://tse1.mm.bing.net/th?id=OIP.acchQ02P8HmrmwbjCTwG5AHaHa&pid=Api"));
    _listView.ItemsSource = new ObservableCollection<UserPostViewModel>
    {
        new UserPostViewModel { Picture = ImageSource.FromResource("Logo"), PostOwner="Kevin Wang", PostOwnerLocation="SHDR"},
        new UserPostViewModel { Picture = pic, PostOwner="Lily", PostOwnerLocation="SHDR"},
        new UserPostViewModel { Picture = pic, PostOwner="Zhang Shuo", PostOwnerLocation="FRDL"},
    };
}

//NOTE: In your Pages ListView DataTemplate
<ListView.ItemTemplate>
    <DataTemplate>
        <ViewCell>
            <local:UserPostView/>
        </ViewCell>
    </DataTemplate>
</ListView.ItemTemplate>

public TimelinePage（）
{
初始化组件（）；
ImageSource pic=ImageSource.FromUri（新Uri（“https://tse1.mm.bing.net/th?id=OIP.acchQ02P8HmrmwbjCTwG5AHaHa&pid=Api"));
_listView.ItemsSource=新的ObservableCollection
{
新用户postViewModel{Picture=ImageSource.FromResource（“徽标”），PostOwner=“Kevin Wang”，PostOwnerLocation=“SHDR”}，
新用户postViewModel{Picture=pic，PostOwner=“Lily”，PostOwnerLocation=“SHDR”}，
新用户postViewModel{Picture=pic，PostOwner=“Zhang Shuo”，PostOwnerLocation=“FRDL”}，
};
}
//注意：在页面中，ListView数据模板
非常感谢您花时间帮助我！但这些代码都是我的课程。ListView是Xamarin.Forms组件。我想找到一种不使用绑定和东西的更简单的方法。；）但我不确定这是否可能，现在系统似乎忽略了从构造函数传递的值。我指的是未提供的
TimelinePage
的xaml代码，应该显示如何在该页面上设置ListView。如果你想让你的
UserPostView
保持原样，把你的
ListView
切换到
StackLayout
，然后把每个
UserPostView
作为一个孩子单独添加进去。啊哈，好主意！也许ListView不适合这种情况？顺便说一句，这是我的代码：
是的，您的默认数据模板不'；没有传递任何构造函数参数，其中ListView的绑定应该在ViewModel中发挥作用，以及为什么只显示默认值。此外，只要您有一定数量的视图来显示don'；不需要回收。它在UserPostView.xaml中显示原始数据，
NameView
显示
Name
，而不是
Lily
或
Kevin Wang
。
public partial class UserPostView : ContentView
{
    public UserPostView()
    {
        InitializeComponent();
    }
}

//NOTE: in UserPostView.xaml 
<Image Source="{Binding Picture}" BackgroundColor="#ddd" />
<Label Text="{Binding PostOwner}" TextColor="#444" FontAttributes="Bold" Margin="10" />
<Label Text="{Binding PostOwnerLocation}" TextColor="#666" YAlign="Center" />
...

public class UserPostViewModel : INotifyPropertyChanged
{
    ImageSource _picture;

    public ImageSource Picture
    {
       get { return _picture; }
       set 
       {
           _picture = value;
           OnPropertyChanged(nameof(Picture));
        }
    }

    string _postOwner;

    public string PostOwner
    {
        get { return _postOwner; }
        set 
        {
            _postOwner = value;
            OnPropertyChanged(nameof(PostOwner));
        }
    }

    string _postOwnerLocation;

    public string PostOwnerLocation
    {
        get { return _postOwnerLocation; }
        set 
        {
            _postOwnerLocation = value;
            OnPropertyChanged(nameof(PostOwnerLocation));
        }
    }

    ....

    public event PropertyChangedEventHandler PropertyChanged;

    protected void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

public TimelinePage()
{
    InitializeComponent();
    ImageSource pic = ImageSource.FromUri(new Uri("https://tse1.mm.bing.net/th?id=OIP.acchQ02P8HmrmwbjCTwG5AHaHa&pid=Api"));
    _listView.ItemsSource = new ObservableCollection<UserPostViewModel>
    {
        new UserPostViewModel { Picture = ImageSource.FromResource("Logo"), PostOwner="Kevin Wang", PostOwnerLocation="SHDR"},
        new UserPostViewModel { Picture = pic, PostOwner="Lily", PostOwnerLocation="SHDR"},
        new UserPostViewModel { Picture = pic, PostOwner="Zhang Shuo", PostOwnerLocation="FRDL"},
    };
}

//NOTE: In your Pages ListView DataTemplate
<ListView.ItemTemplate>
    <DataTemplate>
        <ViewCell>
            <local:UserPostView/>
        </ViewCell>
    </DataTemplate>
</ListView.ItemTemplate>