C#/WPF：ListView 未更新（但当我检查 Snoop 时，一切看起来都很好）

发布于 2024-07-30 13:22:08 字数 1450 浏览 9 评论 0原文

有谁知道为什么我的 ListView 与以下代码不起作用？我用 Snoop 检查了一下，ItemsSource 似乎没问题（当我启动 Snoop 时，ListView 显示 MyViewModel.MyCollection，但是当用 Visual Studio 调试时，它什么也没显示？）

谢谢！

PS：MainWindow.xaml.cs 具有 DataContext = MainViewModel

    <ListView Grid.Row="1" Margin="38,50,0,168" HorizontalAlignment="Left" Name="listViewSelectDate" Width="105"
              ItemsSource="{Binding Path=MyViewModel.MyCollection}" 
              SelectedItem="{Binding SelectedDate}" IsSynchronizedWithCurrentItem="True">
        <ListView.View>
            <GridView>
                <GridViewColumn Header="Date" DisplayMemberBinding="{Binding Path=CalcDate}"/>
            </GridView>
        </ListView.View>
    </ListView>

如下所示：

class MainViewModel : ViewModelBase
{
    public SummaryViewModel MyViewModel
    {
        get { return _myViewModel; }
        set { _myViewModel = value; RaisePropertyChanged("MyViewModel"); }
    }
    public MyDate SelectedDate
    {
        get { return _selectedDate; }
        set { _selectedDate = value; RaisePropertyChanged("SelectedDate"); }
    }
}

和

public class SummaryViewModel : ViewModelBase
{
    public ObservableCollection<MyDate> MyCollection { get; set; }
}

ViewModel

public class MyDate
{
    public DateTime CalcDate { get; set; }
}

原文

Does anyone know why my ListView with following Code is not working?
I checked it out with Snoop and the ItemsSource seems to be fine (and when I start Snoop, the ListView displays me the MyViewModel.MyCollection, but when debugging with Visual Studio it shows me nothing?)

Thank you!

PS: MainWindow.xaml.cs has the DataContext = MainViewModel

    <ListView Grid.Row="1" Margin="38,50,0,168" HorizontalAlignment="Left" Name="listViewSelectDate" Width="105"
              ItemsSource="{Binding Path=MyViewModel.MyCollection}" 
              SelectedItem="{Binding SelectedDate}" IsSynchronizedWithCurrentItem="True">
        <ListView.View>
            <GridView>
                <GridViewColumn Header="Date" DisplayMemberBinding="{Binding Path=CalcDate}"/>
            </GridView>
        </ListView.View>
    </ListView>

The ViewModel looks like this:

class MainViewModel : ViewModelBase
{
    public SummaryViewModel MyViewModel
    {
        get { return _myViewModel; }
        set { _myViewModel = value; RaisePropertyChanged("MyViewModel"); }
    }
    public MyDate SelectedDate
    {
        get { return _selectedDate; }
        set { _selectedDate = value; RaisePropertyChanged("SelectedDate"); }
    }
}

and

public class SummaryViewModel : ViewModelBase
{
    public ObservableCollection<MyDate> MyCollection { get; set; }
}

and

public class MyDate
{
    public DateTime CalcDate { get; set; }
}

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作业与我同在 2024-08-06 13:22:08

谁设置MyCollection？它不提供更改通知，因此绑定不知道它已更改。更改为：

private ObservableCollection<MyDate> _myCollection;
public ObservableCollection<MyDate> MyCollection
{
    get { return _myCollection; }
    set
    {
        _myCollection = value;
        OnPropertyChanged("MyCollection");
    }
}

或者更好的是，将其设为只读：

private readonly ICollection<MyDate> _myCollection = new ObservableCollection<MyDate>();

public ICollection<MyDate> MyCollection
{
    get { return _myCollection; }
}

Who sets MyCollection? It is not providing change notification, so the binding doesn't know that it has been changed. Change to:

private ObservableCollection<MyDate> _myCollection;
public ObservableCollection<MyDate> MyCollection
{
    get { return _myCollection; }
    set
    {
        _myCollection = value;
        OnPropertyChanged("MyCollection");
    }
}

Or, even better, make it read-only:

private readonly ICollection<MyDate> _myCollection = new ObservableCollection<MyDate>();

public ICollection<MyDate> MyCollection
{
    get { return _myCollection; }
}

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