我正在研究一个Xamarin项目,以了解它是如何工作的,但是我遇到了一个我似乎无法解决的问题。ListView.ItemTemplate没有被设置和事件没有被触发
我有一个列表视图itemplate存储在我的XAML中的listview标签内,它定义了一个标签,并且该标签的文本是从数据源绑定的集合,但是当我的项目通过itemsource加载时,重写tostring而不是我的绑定,这会导致问题。我的itemtapped事件处理程序也没有工作,似乎并没有解雇。我正在使用VS for mac。
这里是我的XAML的形式
<?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="BrainStorageApp.MainPage"
Title="View Notes">
<ListView ItemsSource="{Binding Items}"
x:Name="MainListView"
HasUnevenRows="true"
IsGroupingEnabled="true"
IsPullToRefreshEnabled="true"
IsEnabled="true"
CachingStrategy="RecycleElement"
IsRefreshing="{Binding IsBusy, Mode=OneWay}"
RefreshCommand="{Binding RefreshDataCommand}">
<ListView.Header>
<StackLayout Padding="40"
Orientation="Horizontal"
HorizontalOptions="FillAndExpand"
BackgroundColor="{StaticResource Primary}}">
<Label Text="Your Notes"
HorizontalTextAlignment="Center"
HorizontalOptions="FillAndExpand"
TextColor="White"
FontAttributes="Bold"/>
</StackLayout>
</ListView.Header>
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<Label Text="{Binding title}" FontSize="14" />
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</ContentPage>
希望我不只是愚蠢和缺少的东西,因为我的XAML似乎建立罚款和我的ItemSource似乎很好地工作。如果你需要看我的代码只是评论,我会编辑提供。
编辑:不确定它是否有任何区别,但此页面位于Tab键页面。
编辑2:这是我的主要xaml.cs文件的代码,根据要求。
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Input;
using Xamarin.Forms;
using Xamarin.Forms.Xaml;
namespace BrainStorageApp
{
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class MainPage : ContentPage
{
private BrainstorageApiClass BrainstorageClass;
private UserClass User;
public MainPage(string username)
{
InitializeComponent();
BrainstorageClass = new BrainstorageApiClass();
User = new UserClass();
User.Username = username;
BindingContext = new ListViewPageViewModel(BrainstorageClass.LoadNotes(User.Username));
}
void Handle_ItemTapped(object sender, Xamarin.Forms.ItemTappedEventArgs e)
{
Console.WriteLine(sender.ToString());
}
}
class ListViewPageViewModel : INotifyPropertyChanged
{
public ObservableCollection<NoteItem> Items { get; }
public ListViewPageViewModel(List<NoteItem> list)
{
Items = new ObservableCollection<NoteItem>(list);
RefreshDataCommand = new Command(
async() => await RefreshData());
}
public ICommand RefreshDataCommand { get; }
async Task RefreshData()
{
IsBusy = true;
//Load Data Here
await Task.Delay(2000);
IsBusy = false;
}
bool busy;
public bool IsBusy
{
get { return busy; }
set
{
busy = value;
OnPropertyChanged();
((Command)RefreshDataCommand).ChangeCanExecute();
}
}
public event PropertyChangedEventHandler PropertyChanged;
void OnPropertyChanged([CallerMemberName]string propertyName = "") =>
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
编辑3:
NoteItem
namespace BrainStorageApp
{
public class NoteItem
{
public int id;
public string title;
public string content;
public DateTime createdat;
public DateTime updatedat;
public NoteItem(JToken Token)
{
id = int.Parse(Token["id"].Value<string>());
title = Token["Note_Title"].Value<string>();
content = Token["Note_Content"].Value<string>();
createdat = DateTime.Parse(Token["created_at"].Value<string>());
updatedat = DateTime.Parse(Token["updated_at"].Value<string>());
}
public override string ToString()
{
return title;
}
}
}
请显示ViewModel以及如何设置您的BindingContext。 –
@ Sven-MichaelStübe新增:)注意我删除了事件处理程序,因为我认为可以修复此问题的结果:P – Jaxi
和'NoteItem'? –