我有一个问题,我在我的应用程序中尝试在ListView
中显示数据时将数据列表绑定到XAML中的ListView。 ListView根本不会填充任何数据。
这是我的所有编码:
我的代码背后
public ObservableCollection<RandomList> randomList = new ObservableCollection<RandomList>();
public App()
{
MainPage = new MainUI();
randomList.Add(new RandomList { Name = "Susan", Surname = "Potgieter", School = "Oosterlig" });
randomList.Add(new RandomList { Name = "Jonathan", Surname = "Visagie", School = "Elspark" });
randomList.Add(new RandomList { Name = "Gerhard", Surname = "Vermaak", School = "E.G. Jansen" });
randomList.Add(new RandomList { Name = "Kobus", Surname = "Jacobs", School = "Oosterlig" });
}
我的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="RandomTest.MainUI">
<StackLayout Padding="0,40,0,0">
<Label Text="Hello" VerticalOptions="Center" HorizontalOptions="Center" />
<Button x:Name="btnGetStudents" Text="Get Students"/>
<ListView x:Name="lwStudents" ItemsSource="{Binding randomList}">
<ListView.ItemTemplate>
<DataTemplate>
<TextCell Text="{Binding Name}" Detail="{Binding Surname}"/>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</StackLayout>
</ContentPage>
当我在我的代码中插入断点后,我将虚拟数据添加到列表中,然后我可以在我的XAML中看到:<ListView x:Name="lwStudents" ItemsSource="{Binding randomList}">
我的randomList
中有4个项目。
问题是以下两个绑定中没有数据:
<TextCell Text="{Binding Name}" Detail="{Binding Surname}"/>
有人可以告诉或告诉我在绑定中我做错了什么吗?或者,如果您需要任何更多信息或代码,请询问!我很乐意提供更多信息。 :)
编辑
我已经更新了我的RandomList
类并实现了INotifyPropertyChanged
,但我仍然无法通过XAML绑定将我的数据加载到我的ListView中。
using System.ComponentModel;
namespace RandomTest
{
public class RandomList : INotifyPropertyChanged
{
public int Id { get; set; }
string _name;
public string Name
{
get { return _name; }
set
{
if (_name != value)
_name = value;
OnPropertyChanged("Name");
}
}
string _surname;
public string Surname
{
get { return _surname; }
set
{
if (_surname != value)
_surname = value;
OnPropertyChanged("Surname");
}
}
string _school;
public string School
{
get { return _school; }
set
{
if (_school != value)
_school = value;
OnPropertyChanged("School");
}
}
public event PropertyChangedEventHandler PropertyChanged;
void OnPropertyChanged(string propertyName)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
}
编辑2
这就是我的MainUI.xaml.cs页面目前的样子:
public partial class MainUI : ContentPage
{
public MainUI()
{
InitializeComponent();
BindingContext = new MainUIModel();
MainUIModel mainUIModel = (MainUIModel)this.BindingContext;
mainUIModel.randomList.Add(new RandomList { Name = "Susan", Surname = "Potgieter", School = "Oosterlig" });
mainUIModel.randomList.Add(new RandomList { Name = "Jonathan", Surname = "Visagie", School = "Elspark" });
mainUIModel.randomList.Add(new RandomList { Name = "Gerhard", Surname = "Vermaak", School = "E.G. Jansen" });
mainUIModel.randomList.Add(new RandomList { Name = "Kobus", Surname = "Jacobs", School = "Oosterlig" });
}
}
创建MainUIModel模型
public class MainUIModel : INotifyPropertyChanged
{
ObservableCollection<RandomList> _randomList;
public ObservableCollection<RandomList> randomList
{
get { return _randomList; }
set
{
if (_randomList != value)
_randomList = value;
OnPropertyChanged("randomList");
}
}
public event PropertyChangedEventHandler PropertyChanged;
void OnPropertyChanged(string propertyName)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
然后在MainUI页面中,在初始化组件之后设置绑定上下文。
BindingContext = new MainUIModel();
Xaml中的绑定randomList将引用此新创建的模型,您的Name,Surname将引用列表模型。两种绑定上下文都不同。您可以使用以下代码添加数据。
MainUIModel mainUIModel = (MainUIModel)this.BindingContext;
mainUIModel.randomList=new ObservableCollection<RandomList>();
mainUIModel.randomList.Add(new RandomList { Name = "Susan", Surname = "Potgieter", School = "Oosterlig" });
mainUIModel.randomList.Add(new RandomList { Name = "Jonathan", Surname = "Visagie", School = "Elspark" });
mainUIModel.randomList.Add(new RandomList { Name = "Gerhard", Surname = "Vermaak", School = "E.G. Jansen" });
mainUIModel.randomList.Add(new RandomList { Name = "Kobus", Surname = "Jacobs", School = "Oosterlig" });
真的你需要做的就是确保ObservableCollection
有一个public getter
。然后你可以设置BindingContext = this
,你可以在UI上访问它。但与往常一样,有许多方法可以为这些小猫提供皮肤。