TreeView 和数据绑定失败

Question

我正在使用 MVVM 模式和 TreeView。

我未能将数据模型与视图绑定。这是我当前的代码：

MainWindow.xaml:

xmlns:reptile="clr-namespace:Terrario.Models.Reptile"
...
<TreeView x:Name="TrvFamily" Grid.Row="1" Grid.Column="0" ItemsSource="{Binding }">
            <TreeView.ItemTemplate>
                <HierarchicalDataTemplate DataType="{x:Type reptile:Family}" ItemsSource="{Binding Items}">
                    <TextBlock Text="{Binding Name}" />
                </HierarchicalDataTemplate>
            </TreeView.ItemTemplate>
        </TreeView>

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        LoadFamily();
    }

MainWindow.xaml.cs:

    private void LoadFamily()
    {
        FamilyVM familiesVM = new FamilyVM();
        familiesVM.Load();
        TrvFamily.DataContext = familiesVM;
    }
}

ViewModels\FamilyVM:

class FamilyVM
{
    public ObservableCollection<Family> Families { get; set; }

    public void Load()
    {
        ObservableCollection<Family> families = new ObservableCollection<Family>();

        families.Add(new Family { ID = 1, Name = "Amphibian" });
        families.Add(new Family { ID = 2, Name = "Viperidae" });
        families.Add(new Family { ID = 3, Name = "Aranae" });

        Families = families;
    }
}

Models\Family.cs

    class Family
{
    public int ID { get; set; }
    public string Name { get; set; }
}

TreeView 还是白色的，好像没有数据。

希望你有问题 ;)

谢谢预付

Answer 1

您正在绑定到 FamilyVM 实例而不是 Families。那没有名字属性，所以你什么也得不到。

您还应该始终在任何视图模型上实施 inotify属性changed。否则你会发生内存泄漏。

并且您在“家庭”上没有子集合。

    <TreeView x:Name="TrvFamily" Grid.Row="1"
              ItemsSource="{Binding Families}">
        <TreeView.ItemTemplate>
            <HierarchicalDataTemplate DataType="{x:Type local:Family}" ItemsSource="{Binding SomeCollectionYouDoNotHaveYet}">
                <TextBlock Text="{Binding Name}" />
            </HierarchicalDataTemplate>
        </TreeView.ItemTemplate>
    </TreeView>

通常将 inotify属性更改的内容放在您从中继承视图模型的基础 class 中。

class FamilyVM : INotifyPropertyChanged
{
    private ObservableCollection<Family> families = new ObservableCollection<Family>();

    public ObservableCollection<Family> Families
    {
        get { return families; }
        set { families = value; NotifyPropertyChanged(); }
    }

    public void Load()
    {
        ObservableCollection<Family> families = new ObservableCollection<Family>();
        families.Add(new Family { ID = 1, Name = "Amphibian" });
        families.Add(new Family { ID = 2, Name = "Viperidae" });
        families.Add(new Family { ID = 3, Name = "Aranae" });
        Families = families;
    }
    public event PropertyChangedEventHandler PropertyChanged;
    private void NotifyPropertyChanged([CallerMemberName] String propertyName = "")
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

TreeView 和数据绑定失败

TreeView and databinding failed

c#

data-binding

wpf

observablecollection

mvvm