未找到绑定属性/某些数据未显示
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【中文标题】未找到绑定属性/某些数据未显示【英文标题】：Binding property not found / some data displayed some not 【发布时间】：2021-01-23 23:03:45 【问题描述】：我在显示数据时遇到问题，我可以在 List 属性中看到我的数据 FieldValue 和 FieldDescriptor 但是我仍然在输出中看到：
绑定：在“ViewModel.ResultPageViewModel”上找不到“Results”属性，目标属性：“Xamarin.Forms.ListView.ItemsSource”
我在水平列表视图中看不到任何数据FieldVisualData，即使我可以在视图模型中看到它们添加到细节并且也找不到命令。
绑定：在“Model.DocumentData”上找不到“EditTextCommand”属性，目标属性：“Xamarin.Forms.TapGestureRecognizer.Command”
也许你看到了我遗漏的东西？
<StackLayout Spacing="0">
<!--Pictures-->
<StackLayout VerticalOptions="Start" Spacing="0" >
<controls:HorizontalScrollList VerticalOptions="Start" HeightRequest="300" x:Name="carouselView" ItemsSource="Binding Results, Mode=TwoWay">
<controls:HorizontalScrollList.ItemTemplate>
<DataTemplate>
<Image Source="Binding Results.FieldVisualData"
Margin="5">
<!--<Image.GestureRecognizers>
<TapGestureRecognizer
Command="Binding HandlePreviewTapped, Source=x:Reference vm"
CommandParameter="Binding"/>
</Image.GestureRecognizers>-->
</Image>
</DataTemplate>
</controls:HorizontalScrollList.ItemTemplate>
</controls:HorizontalScrollList>
</StackLayout>
<StackLayout VerticalOptions="Start" BackgroundColor="DynamicResource SeparatorLineColor" Spacing="10">
<!--DocumentData-->
<Label Grid.Row="0" HorizontalOptions="CenterAndExpand" Text="Občanský průkaz" VerticalOptions="End" ></Label>
<StackLayout BackgroundColor="DynamicResource PageBackgroundColor" VerticalOptions="FillAndExpand">
<ListView x:Name="list" BackgroundColor="DynamicResource PageBackgroundColor"
HasUnevenRows="True"
HorizontalOptions="CenterAndExpand"
VerticalOptions="CenterAndExpand"
VerticalScrollBarVisibility="Never"
CachingStrategy="RecycleElement"
ItemsSource="Binding Results, Mode=TwoWay"
SeparatorVisibility="Default"
SelectionMode="None">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<Grid BackgroundColor="DynamicResource PageBackgroundColor" Padding="10" >
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="15*"/>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="12*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Label Grid.Column="1" Padding="0" Text ="Binding FieldDescriptor" Style="StaticResource SubLabelBlackStyle" HorizontalOptions="Start" BackgroundColor="DynamicResource PageBackgroundColor" HorizontalTextAlignment="Start"/>
<Label Grid.Column="3" Padding="0" Text="Binding FieldValue" FontSize="Small" TextColor="#6781a3" BackgroundColor="DynamicResource PageBackgroundColor" HorizontalOptions="Start" HorizontalTextAlignment="Start">
<Label.GestureRecognizers>
<TapGestureRecognizer Command="Binding EditTextCommand" CommandParameter="Binding FieldValue" />
</Label.GestureRecognizers>
</Label>
</Grid>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</StackLayout>
</StackLayout>
</StackLayout>
public partial class ResultPage : ContentPage
public ResultPage(IEnumerable<DocumentData> data)
InitializeComponent();
BindingContext = new ResultPageViewModel(data);
//carouselView.ItemsSource = data;
// list.ItemsSource = data;
public class ResultPageViewModel : BaseViewModel
public ObservableCollection<DocumentData> Results get; = new ObservableCollection<DocumentData>();
public ICommand EditTextCommand get;
object param = "";
public ResultPageViewModel(IEnumerable<DocumentData> data)
EditTextCommand = new Command(async () => await EditTextAsync(param));
Load(data);
public void Load(IEnumerable<DocumentData> data)
foreach (var result in data)
var detail = new DocumentData()
FieldVisualData = result.FieldVisualData,
FieldDescriptor = result.FieldDescriptor,
FieldValue = result.FieldValue,
;
Results.Add(detail);
public async Task EditTextAsync(object param)
PromptResult pResult = await UserDialogs.Instance.PromptAsync(new PromptConfig
InputType = InputType.Password,
Text = param.ToString(),
Title = Resources.AppResources.Password_lbl,
);
public static readonly BindableProperty ItemTemplateProperty = BindableProperty.Create( "项目模板", 类型（数据模板）， typeof(HorizontalScrollList), 空值， propertyChanged: (bindable, value, newValue) => ((HorizontalScrollList)bindable).Populate());
public static readonly BindableProperty ItemsSourceProperty = BindableProperty.Create(
"ItemsSource",
typeof(IEnumerable),
typeof(HorizontalScrollList),
null,
BindingMode.OneWay,
propertyChanged: (bindable, value, newValue) =>
var obs = value as INotifyCollectionChanged;
var self = (HorizontalScrollList)bindable;
if (obs != null)
obs.CollectionChanged -= self.HandleItemChanged;
self.Populate();
obs = newValue as INotifyCollectionChanged;
if (obs != null)
obs.CollectionChanged += self.HandleItemChanged;
);
public IEnumerable ItemsSource
get => (IEnumerable)this.GetValue(ItemsSourceProperty);
set => this.SetValue(ItemsSourceProperty, value);
public DataTemplate ItemTemplate
get => (DataTemplate)this.GetValue(ItemTemplateProperty);
set => this.SetValue(ItemTemplateProperty, value);
private bool willUpdate = true;
private void HandleItemChanged(object sender, NotifyCollectionChangedEventArgs eventArgs)
if (!willUpdate)
willUpdate = true;
Device.BeginInvokeOnMainThread(Populate);
public HorizontalScrollList()
this.Orientation = ScrollOrientation.Horizontal;
private void Populate()
willUpdate = false;
Content = null;
if (ItemsSource == null || ItemTemplate == null)
return;
var list = new StackLayout Orientation = StackOrientation.Horizontal ;
foreach (var viewModel in ItemsSource)
var content = ItemTemplate.CreateContent();
if (!(content is View) && !(content is ViewCell))
throw new Exception($"Invalid visual object nameof(content)");
var view = content is View ? content as View : ((ViewCell)content).View;
view.BindingContext = viewModel;
list.Children.Add(view);
if (list.Children.Count == 0)
list.Padding = 20;
list.Children.Add(new Label
WidthRequest = (list as VisualElement).Width - 30,
HorizontalOptions = new LayoutOptions(LayoutAlignment.Fill, true),
VerticalOptions = new LayoutOptions(LayoutAlignment.Fill, true),
HorizontalTextAlignment = TextAlignment.Center,
VerticalTextAlignment = TextAlignment.Center,
FontSize = 15,
);
Content = list;
【问题讨论】：
EditTextCommand 是 VM 的属性，而不是 DocumentData。 LIstView 中的每一行都绑定到一个 DocumentData 对象。如果要引用父 VM 上的属性，请参阅docs.microsoft.com/en-us/xamarin/xamarin-forms/app-fundamentals/… 根据您的描述，很难确定哪些数据有效，哪些无效。请编辑您的问题，以更清楚地说明哪些特定元素导致了问题 【参考方案1】：你想达到像下面的 GIF 一样的结果吗？
我不知道你设置的是哪种样式或背景色，我设置的是静态背景色。
这是我编辑后的布局。controls:HorizontalScrollList 是一张图片，所以我评论它。
我更改了TapGestureRecognizer中的命令
<StackLayout Spacing="0">
<!--Pictures-->
<StackLayout VerticalOptions="Start" Spacing="0" >
<!--<controls:HorizontalScrollList VerticalOptions="Start" HeightRequest="300" x:Name="carouselView" ItemsSource="Binding Results, Mode=TwoWay">
<controls:HorizontalScrollList.ItemTemplate>
<DataTemplate>
<Image Source="Binding Results.FieldVisualData"
Margin="5">
--><!--<Image.GestureRecognizers>
<TapGestureRecognizer
Command="Binding HandlePreviewTapped, Source=x:Reference vm"
CommandParameter="Binding"/>
</Image.GestureRecognizers>--><!--
</Image>
</DataTemplate>
</controls:HorizontalScrollList.ItemTemplate>
</controls:HorizontalScrollList>-->
</StackLayout>
<StackLayout VerticalOptions="Start" BackgroundColor="White" Spacing="10">
<!--DocumentData-->
<Label Grid.Row="0" HorizontalOptions="CenterAndExpand" Text="Občanský průkaz" VerticalOptions="End" ></Label>
<StackLayout BackgroundColor="Green" VerticalOptions="FillAndExpand">
<ListView x:Name="list" BackgroundColor="Red"
HasUnevenRows="True"
HorizontalOptions="CenterAndExpand"
VerticalOptions="CenterAndExpand"
VerticalScrollBarVisibility="Never"
CachingStrategy="RecycleElement"
ItemsSource="Binding Results, Mode=TwoWay"
SeparatorVisibility="Default"
SelectionMode="None">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<Grid BackgroundColor="Beige" Padding="10" >
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="15*"/>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="12*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Label Grid.Column="1" Padding="0" Text ="Binding FieldDescriptor" HorizontalOptions="Start" BackgroundColor="Gray" HorizontalTextAlignment="Start"/>
<Label Grid.Column="3" Padding="0" Text="Binding FieldValue" FontSize="Small" TextColor="#6781a3" BackgroundColor="AliceBlue" HorizontalOptions="Start" HorizontalTextAlignment="Start">
<Label.GestureRecognizers>
<TapGestureRecognizer
Command="Binding BindingContext.EditTextCommand, Source=x:Reference Name=list"
CommandParameter="Binding ."
/>
</Label.GestureRecognizers>
</Label>
</Grid>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</StackLayout>
</StackLayout>
</StackLayout>
这是布局背景代码。我添加三个数据来做一个测试。
public partial class MainPage : ContentPage
public MainPage()
InitializeComponent();
IEnumerable<DocumentData> data = new DocumentData[] new DocumentData() FieldDescriptor="test 1", FieldValue=1, FieldVisualData=1 ;
data = data.Append(new DocumentData() FieldDescriptor = "test 2", FieldValue = 2, FieldVisualData = 2 );
data = data.Append(new DocumentData() FieldDescriptor = "test 3", FieldValue = 3, FieldVisualData = 3 );
this.BindingContext = new ResultPageViewModel(data);
这里是ResultPageViewModels 代码。
using Acr.UserDialogs;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Input;
using Xamarin.Forms;
namespace XFormsListviewMvvm
public class ResultPageViewModel : BaseViewModel
public ObservableCollection<DocumentData> Results get; = new ObservableCollection<DocumentData>();
public ICommand EditTextCommand get;
object param = "";
public ResultPageViewModel(IEnumerable<DocumentData> data)
EditTextCommand = new Command<DocumentData>(async (key) => await EditTextAsync(key));
Load(data);
public void Load(IEnumerable<DocumentData> data)
foreach (var result in data)
var detail = new DocumentData()
FieldVisualData = result.FieldVisualData,
FieldDescriptor = result.FieldDescriptor,
FieldValue = result.FieldValue,
;
Results.Add(detail);
public async Task EditTextAsync(DocumentData param)
PromptResult pResult = await UserDialogs.Instance.PromptAsync(new PromptConfig
InputType = InputType.Password,
Text = param.FieldValue.ToString(),
Title = "Insert your Password",
);
if (pResult.Ok)
param.FieldValue = pResult.Text;
如果您需要更改值，则布局将显示它。您需要在DocumentData 中实现BaseViewModel。
namespace XFormsListviewMvvm
public class DocumentData:BaseViewModel
private object fieldVisualData = "Hello world";
public object FieldVisualData
get => fieldVisualData;
set => SetValue(ref fieldVisualData, value);
private object fieldValue = "Hello world";
public object FieldValue
get => fieldValue;
set => SetValue(ref fieldValue, value);
public object FieldDescriptor get; internal set;
=============更新===================
我添加了您的controls:HorizontalScrollList 代码。我将 <Image Source="Binding Results.FieldVisualData"> 更改为 <Image Source="Binding FieldVisualData" >
这里是运行gif。图片可以正常看到了。
这是编辑后的布局。
<StackLayout Spacing="0">
<!--Pictures-->
<StackLayout VerticalOptions="Start" Spacing="0" >
<controls:HorizontalScrollList VerticalOptions="Start" HeightRequest="300" x:Name="carouselView" ItemsSource="Binding Results, Mode=TwoWay">
<controls:HorizontalScrollList.ItemTemplate>
<DataTemplate>
<Image Source="Binding FieldVisualData"
Margin="5">
<!--<Image.GestureRecognizers>
<TapGestureRecognizer
Command="Binding HandlePreviewTapped, Source=x:Reference vm"
CommandParameter="Binding"/>
</Image.GestureRecognizers>-->
</Image>
</DataTemplate>
</controls:HorizontalScrollList.ItemTemplate>
</controls:HorizontalScrollList>
</StackLayout>
<StackLayout VerticalOptions="Start" BackgroundColor="White" Spacing="10">
<!--DocumentData-->
<Label Grid.Row="0" HorizontalOptions="CenterAndExpand" Text="Občanský průkaz" VerticalOptions="End" ></Label>
<StackLayout BackgroundColor="Green" VerticalOptions="FillAndExpand">
<ListView x:Name="list" BackgroundColor="Red"
HasUnevenRows="True"
HorizontalOptions="CenterAndExpand"
VerticalOptions="CenterAndExpand"
VerticalScrollBarVisibility="Never"
CachingStrategy="RecycleElement"
ItemsSource="Binding Results, Mode=TwoWay"
SeparatorVisibility="Default"
SelectionMode="None">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<Grid BackgroundColor="Beige" Padding="10" >
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="15*"/>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="12*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Label Grid.Column="1" Padding="0" Text ="Binding FieldDescriptor" HorizontalOptions="Start" BackgroundColor="Gray" HorizontalTextAlignment="Start"/>
<Label Grid.Column="3" Padding="0" Text="Binding FieldValue" FontSize="Small" TextColor="#6781a3" BackgroundColor="AliceBlue" HorizontalOptions="Start" HorizontalTextAlignment="Start">
<Label.GestureRecognizers>
<TapGestureRecognizer
Command="Binding BindingContext.EditTextCommand, Source=x:Reference Name=list"
CommandParameter="Binding ."
/>
</Label.GestureRecognizers>
</Label>
</Grid>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</StackLayout>
</StackLayout>
</StackLayout>
这是布局背景代码。
public partial class MainPage : ContentPage
public MainPage()
InitializeComponent();
IEnumerable<DocumentData> data = new DocumentData[] new DocumentData() FieldDescriptor="test 1", FieldValue=1, FieldVisualData= "https://aka.ms/campus.jpg" ;
data = data.Append(new DocumentData() FieldDescriptor = "test 2", FieldValue = 2, FieldVisualData = "https://aka.ms/campus.jpg" );
data = data.Append(new DocumentData() FieldDescriptor = "test 3", FieldValue = 3, FieldVisualData = "https://aka.ms/campus.jpg" );
this.BindingContext = new ResultPageViewModel(data);
【讨论】：
嗨，谢谢，这看起来不错。但是我的主要问题是为什么我无法获取图片：D 你是指controls:HorizontalScrollList中的图片吗？
你能分享controls:HorizontalScrollList代码吗？
谢谢，它成功了。我已经接受了答案，但感谢您在接受答案后继续帮助我。以上是关于未找到绑定属性/某些数据未显示的主要内容，如果未能解决你的问题，请参考以下文章