Xamarin.Forms Tapped 事件，没有可绑定的属性

Posted 2023-03-12

【中文标题】Xamarin.Forms Tapped 事件，没有可绑定的属性

【英文标题】：Xamarin.Forms Tapped event, no bindable property

【发布时间】：2021-03-31 18:16:09

【问题描述】：

我正在尝试获取从 ViewModel 填充的 ListView。参考 *** 文章，这应该是一个可行的解决方案。这篇文章可以在这里找到ListView not triggering ItemTapped。

尝试编译时出现以下错误：

No property, BindableProperty, or event found for "ItemTapped", or mismatching type between value and property.

如果我从 xaml 文件中删除 ItemTapped，项目将编译并填充列表。最终目标是使 ListView 中的每个项目都可点击，从而指向特定的站点。

下面是我的代码的sn-ps

StationSelectorPage.xaml

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="Company.Forms.Views.StationSelectorPage"
            xmlns:vm="clr-namespace:Company.Forms.ViewModels"
             Title="Binding Title">
    <ContentPage.BindingContext>
        <vm:StationSelectorViewModel />
    </ContentPage.BindingContext>

    <ContentPage.Content>
        <StackLayout>
            
            <Label Text="Select Station:" />
            
            <ListView 
                x:Name="StationView" 
                ItemsSource="Binding Stations"
                ItemTapped="Binding OnItemTapped">
                <ListView.ItemTemplate>
                    <DataTemplate>
                        <TextCell Text="Binding StationName" />
                    </DataTemplate>
                </ListView.ItemTemplate>
            </ListView>
        </StackLayout>
    </ContentPage.Content>
</ContentPage>

StationSelectorPage.xaml.cs

    [XamlCompilation(XamlCompilationOptions.Compile)]
    public partial class StationSelectorPage : ContentPage
    
        
        public StationSelectorPage()
        
            InitializeComponent();
        
    

StationSelectorViewModel.cs

public class StationSelectorViewModel : BaseViewModel

    public List<StationsModel> m_Stations;
    public List<AreasModel> m_Areas;
    public ApiConnection m_apiConnection;
    ObservableCollection<StationsModel> stations = new ObservableCollection<StationsModel>();
    public ObservableCollection<StationsModel> Stations  get  return stations; 


    public StationSelectorViewModel()
    
        Title = "Station Selector";
        m_apiConnection = new ApiConnection(Constants.Url, null, null);
        GetStations();
    

    public async void GetStations()
    
        string absolutePath = DependencyService.Get<IMisc>().GetAbsolutePath();

        m_Areas = await m_apiConnection.HttpGetAsync<List<AreasModel>>("misc/get-areas");

        m_Stations = 
            m_Areas.
            Select(x => new StationsModel  StationId = x.StationId, StationName = x.StationName )
            .Distinct()
            .ToList();

        foreach(var station in m_Stations)
        
            Stations.Add(new StationsModel  StationId = station.StationId, StationName = station.StationName );
        

    


    public async void OnItemTapped(object group, object item, int itemIndex)
    
        var selectedItem = item;
    

【参考方案1】：

ItemTapped 处理程序的签名是

void ItemTappedHandler(object sender, Xamarin.Forms.ItemTappedEventArgs args)

【讨论】：

我将函数调整为：public async void OnItemTapped(object sender, Xamarin.Forms.ItemTappedEventArgs args) System.Console.WriteLine("Testing"); 这给我带来了与No property, BindableProperty, or event found for "ItemTapped", or mismatching type between value and property. 相同的错误

啊，我没听懂。我不认为你绑定事件处理程序。

这种方式不能绑定 OnItemTapped 事件。你可以用Xamarin Community Toolkit ItemTappedEventArgsConverter这个video also explains怎么用好。