c# - WPF MVVM 层次结构选择项

Question

我目前正在使用ListBoxes 实现显示hierarchy 的应用程序(请不要建议使用TreeView、ListBoxes 是必需的)。

看起来像那样in the article: WPF’s CollectionViewSource (with source code) .

类:

public class Mountains : ObservableCollection<Mountain>
{
    public ObservableCollection<Lift> Lifts { get; }

    public string Name { get; }
}

public class Lift
{
    public ObservableCollection<string> Runs { get; }
}

该示例使用 CollectionViewSource 实例(参见 XAML)来简化设计。Mountains 类的实例是窗口的 DataContext。

---

问题是:我希望 Mountains 类具有 SelectedRun 属性，并且它应该设置为当前选择的运行。

public class Mountains : ObservableCollection<Mountain>
{
    public ObservableCollection<Lift> Lifts { get; }

    public string Name { get; }

    public string SelectedRun { get; set; }
}

也许我错过了一些基本原则，但我怎样才能做到这一点？

Answer 1

您可能想阅读有关在绑定(bind)中使用“/”的信息。请参阅此 MSDN article 上的“当前项目指针”部分.

这是我的解决方案:

Xaml

    <Grid.RowDefinitions>
        <RowDefinition Height="Auto"/>
        <RowDefinition/>
    </Grid.RowDefinitions>

    <Grid.ColumnDefinitions>
        <ColumnDefinition/>
        <ColumnDefinition/>
        <ColumnDefinition/>
    </Grid.ColumnDefinitions>

    <TextBlock Margin="5" Grid.Row="0" Grid.Column="0" Text="Mountains"/>
    <TextBlock Margin="5" Grid.Row="0" Grid.Column="1" Text="Lifts"/>
    <TextBlock Margin="5" Grid.Row="0" Grid.Column="2" Text="Runs"/>

    <ListBox Grid.Row="1" Grid.Column="0" Margin="5" 
             ItemsSource="{Binding Mountains}" DisplayMemberPath="Name" 
             IsSynchronizedWithCurrentItem="True" />

    <ListBox Grid.Row="1" Grid.Column="1" Margin="5" 
             ItemsSource="{Binding Mountains/Lifts}" DisplayMemberPath="Name" 
             IsSynchronizedWithCurrentItem="True"/>

    <ListBox Grid.Row="1" Grid.Column="2" Margin="5" 
             ItemsSource="{Binding Mountains/Lifts/Runs}" 
             IsSynchronizedWithCurrentItem="True" 
             SelectedItem="{Binding SelectedRun}"/>
</Grid>

C#(注意，您不需要实现 INotifyPropertyChanged 除非属性将被更改而不仅仅是被选中)

public class MountainsViewModel
{
    public MountainsViewModel()
    {
        Mountains = new ObservableCollection<Mountain>
                        {
                            new Mountain
                                {
                                    Name = "Whistler",
                                    Lifts = new ObservableCollection<Lift>
                                                {
                                                    new Lift
                                                        {
                                                            Name = "Big Red",
                                                            Runs = new ObservableCollection<string>
                                                                       {
                                                                           "Headwall",
                                                                           "Fisheye",
                                                                           "Jimmy's"
                                                                       }
                                                        },
                                                    new Lift
                                                        {
                                                            Name = "Garbanzo",
                                                            Runs = new ObservableCollection<string>
                                                                       {
                                                                           "Headwall1",
                                                                           "Fisheye1",
                                                                           "Jimmy's1"
                                                                       }
                                                        },
                                                    new Lift {Name = "Orange"},
                                                }

                                },
                            new Mountain
                                {
                                    Name = "Stevens",
                                    Lifts = new ObservableCollection<Lift>
                                                {
                                                    new Lift {Name = "One"},
                                                    new Lift {Name = "Two"},
                                                    new Lift {Name = "Three"},
                                                }

                                },
                            new Mountain {Name = "Crystal"},
                        };
    }

    public string Name { get; set; }
    private string _selectedRun;
    public string SelectedRun
    {
        get { return _selectedRun; }
        set
        {
            Debug.WriteLine(value);
            _selectedRun = value;
        }
    }

    public ObservableCollection<Mountain> Mountains { get; set; }
}

public class Mountain
{
    public string Name { get; set; }

    public ObservableCollection<Lift> Lifts { get; set; }
}

public class Lift
{
    public string Name { get; set; }

    public ObservableCollection<string> Runs { get; set; }
}