我有一个ListView，要根据接收到的String填充一些项目。我目前有一个Listview，在其中我“手动”添加了一些条目以尝试熟悉 INotifyPropertyChanged 和 ObservableCollection 的概念。我想要做的是有一个图像，当点击ListView项时（它将仅针对该特定点击的ListView项）会发生变化。目前，我只能通过将Image用作ImageButton（Image Tapped Event）来使其工作。在ListView中一起使用这两个属性的正确方法是什么？
我只使用Xamarin和C＃不到两个星期，所以如果答案或建议非常简单，我深表歉意。任何帮助/建议或示例，将不胜感激。提前致谢。
“我的中继”类（具有INotifyPropertyChanged）如下：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using System.Text;
namespace Socket.Models
{
public class Relays : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged([CallerMemberName] string name =
"")
{
PropertyChanged?.Invoke(this, new
PropertyChangedEventArgs(name));
}
//public string ImageUrl { get; set; } // The source of the
Image in the Listview
public int ID { get; set; }
private string _Name;
public string Name // The name of the item in
the ListView
{
get
{
return _Name;
}
set
{
if (_Name != value)
{
_Name = value;
OnPropertyChanged();
}
}
}
private string _ImageUrl;
public string ImageUrl // The name of the
Image in the ListView
{
get
{
return _ImageUrl;
}
set
{
if (_ImageUrl != value)
{
_ImageUrl = value;
OnPropertyChanged();
}
}
}
}
}
RelayControl.xaml.cs类（带有ObservableCollection）如下：
using Socket.Models;
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 Xamarin.Forms;
using Xamarin.Forms.Xaml;
namespace Socket
{
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class RelayControl : ContentPage
{
public Boolean RelayOn=false; // Used to
check the State
public string RelayName; // Used to
test the name change
public string Images; // Used to
change the Image
public int RelayID;
public RelayControl()
{
InitializeComponent ();
Images= "ryno.jpg";
RelayName = "Cool";
loadSampleData();
this.BindingContext = new Relays(); // Binding the
Listview items
var neg = lstView.BindingContext as Relays;
//RelayOn = neg.isOn; // Assign the
Binding OnProperty to the Boolean Variable
RelayName = neg.Name;
Images = neg.ImageUrl;
RelayID = neg.ID;
}
private void loadSampleData()
{
// Create sample data
ObservableCollection<Relays> listRelays = new
ObservableCollection<Relays>();
listRelays.Add(new Relays { Name = "Relay " + 0, ImageUrl
= "ryno.jpg", ID = 0 });
listRelays.Add(new Relays { Name = "Relay " + 1, ImageUrl
="ryno.jpg", ID = 1 }); // num = i
listRelays.Add(new Relays { Name = RelayName, ImageUrl =
Images, ID = 2 });
lstView.ItemsSource = listRelays;
}
public class MyListItemEventArgs : EventArgs
{
public Relays MyItem { get; set; }
public MyListItemEventArgs(Relays item)
{
this.MyItem = item;
}
}
private void ImageCell_Tapped(object sender,
MyListItemEventArgs e)
{
var item = e.MyItem;
if (item == null) return;
if (item.ID == 2)
{
if (RelayOn == true)
{
RelayName = "On";
Images = "on.jpg";
RelayOn = false;
}
else
{
RelayName = "OFF";
Images = "off.jpg";
RelayOn = true;
}
}
loadSampleData();
}
RelayControl.xaml如下：
<?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="Socket.RelayControl"
Title="Relay Control Page">
<ContentPage.Content>
<StackLayout Padding="10,0,0,10" Margin="2">
<!--<SearchBar x:Name="MainSearchBar"
SearchButtonPressed="SearchBar_SearchButtonPressed">
</SearchBar>-->
<ListView x:Name="lstView" SelectionMode="None"
RowHeight="50" >
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell >
<StackLayout Orientation="Vertical">
<StackLayout Orientation="Horizontal">
<Label Text="{Binding Name,
Mode=OneWay}"
x:Name="Received"
TextColor="#f35e20"
VerticalTextAlignment="Center"/>
<Image Source="{Binding ImageUrl,
Mode=OneWay}" Aspect="AspectFit"
HeightRequest="50"
WidthRequest="110"
HorizontalOptions="EndAndExpand"
VerticalOptions="Center">
<Image.GestureRecognizers>
<TapGestureRecognizer
CommandParameter="{Binding .}"
Tapped="ImageCell_Tapped" />
</Image.GestureRecognizers>
</Image>
<!--LabelText="{Binding Name}"
TextColor="DarkGoldenrod" ImageSource="
{Binding ImageUrl}"
Tapped="ImageCell_Tapped">-->
</StackLayout>
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</StackLayout>
</ContentPage.Content>
</ContentPage>