我正在创建ContentView的子类UserPostView
,以用作ListView中的数据模板。我通过创建UserPostView
的新实例动态地将项添加到ListView的ItemSource。
<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" />
并在代码中:
using System;
using System.Collections.Generic;
using Xamarin.Forms;
namespace CMCityClient.Views
{
public partial class UserPostView : ContentView
{
public ImageSource Picture
{
get { return PictureView.Source; }
set { PictureView.Source = value; }
}
public string PostOwner {
get { return NameView.Text; }
set { NameView.Text = value; }
}
public string PostOwnerLocation {
get { return LocationNameView.Text; }
set { LocationNameView.Text = value; }
}
// ...
// ...
public UserPostView(ImageSource picture, string owner, string loc, string dept, string text) {
InitializeComponent();
Picture = picture;
PostOwner = owner;
PostOwnerLocation = loc;
PostOwnerDept = dept;
PostText = text;
}
public UserPostView(ImageSource picture, string owner, string loc, string dept, string text, ImageSource image) {
InitializeComponent();
Picture = picture;
PostOwner = owner;
PostOwnerLocation = loc;
PostOwnerDept = dept;
PostText = text;
PostImage = image;
}
}
}
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。 (文本=&#34;名称&#34; ...)
public TimelinePage()
{
InitializeComponent();
ImageSource pic = ImageSource.FromUri(new Uri("https://tse1.mm.bing.net/th?id=OIP.acchQ02P8HmrmwbjCTwG5AHaHa&pid=Api"));
timeline.ItemsSource = new UserPostView[]{
new UserPostView(ImageSource.FromResource("Logo"), "Kevin Wang", "SHDR", "AOP", "hey"),
new UserPostView(pic, "Lily", "SHDR", "ENT", "good"),
new UserPostView(pic, "Zhang Shuo", "FRDL", "ENT", "Salut! "),
};
}
帮助!如何让它们显示通过构造函数的数据?
答案 0 :(得分:1)
如果您可以提供ListView的xaml和DataTemplate,我们可以为您提供更好的答案。
但是,我的猜测是你的ListView的ItemsSource
应设置为ViewModel : INotifyPropertyChanged
的列表,其中包含您的属性而不是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" />
...
示例ViewModel:
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));
}
}
在你的页面中:
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>