Question

我有以下ViewModel类：

public class ViewModel : INotifyPropertyChanged
{
    public ViewModel()
    {
        m_folders = new List<Folder>();
    }

    private List<Folder> m_folders;
    public List<Folder> Folders
    {
        get { return m_folders; }
        set
        {
            m_folders = value;
            NotifiyPropertyChanged("Folders");
        }
    }

    void NotifiyPropertyChanged(string property)
    {
        if (PropertyChanged != null)
            PropertyChanged(this, new PropertyChangedEventArgs(property));
    }

    public event PropertyChangedEventHandler PropertyChanged;
}

和Folder类：

public class Folder
{
    public Folder()
    {
        Folders = new List<Folder>();
    }

    public string FullPath
    {
        get;
        set;
    }

    public string FolderLabel
    {
        get;
        set;
    }

    public List<Folder> Folders
    {
        get;
        set;
    }
}

ViewModel类被绑定到TreeView，如下所示：

    <TreeView ItemsSource="{Binding Folders}" Margin="10" Height="200" Name="treeView">
        <TreeView.ItemTemplate>
            <HierarchicalDataTemplate ItemsSource="{Binding Folders}" DataType="{x:Type local:Folder}" >
                <TextBlock Text="{Binding FolderLabel}"/>
            </HierarchicalDataTemplate>
        </TreeView.ItemTemplate>
    </TreeView>

绑定本身在Window Load事件中完成，然后填充对象：

    public ViewModel model = new ViewModel();

    private void Window_Loaded(object sender, RoutedEventArgs e)
    {
        treeView.DataContext = model;

        //add Root items
        model.Folders.Add(new Folder { FolderLabel = "Dummy1", FullPath = @"C:\dummy1" });
        model.Folders.Add(new Folder { FolderLabel = "Dummy2", FullPath = @"C:\dummy2" });
        model.Folders.Add(new Folder { FolderLabel = "Dummy3", FullPath = @"C:\dummy3" });
        model.Folders.Add(new Folder { FolderLabel = "Dummy4", FullPath = @"C:\dummy4" });

        //add sub items
        model.Folders[0].Folders.Add(new Folder { FolderLabel = "Dummy11", FullPath = @"C:\dummy11" });
        model.Folders[0].Folders.Add(new Folder { FolderLabel = "Dummy12", FullPath = @"C:\dummy12" });
        model.Folders[0].Folders.Add(new Folder { FolderLabel = "Dummy13", FullPath = @"C:\dummy13" });
        model.Folders[0].Folders.Add(new Folder { FolderLabel = "Dummy14", FullPath = @"C:\dummy14" });

        model.Folders[0].Folders[0].Folders.Add(new Folder { FolderLabel = "MyDummy1", FullPath = @"xxxxxx" });
    }

到目前为止，这么好。一切都很好。然后我向表单添加一个按钮，并从表单加载中删除填充代码并将其放在按钮单击上。它不起作用了。 TreeView绑定不再起作用。我做错了吗？

Answer 1

因为您将TreeView的项目源绑定到List<Folder>。初始绑定将起作用，但进一步的更新不会反映在UI中，因为List<T>内部不实现INotifyPropertyChanged和INotifyCollectionChanged接口。您需要将List<Folder>替换为ObservableCollection<Folder>。

WPF TreeView中的分层绑定无法处理按钮单击

1 个答案: