C# 带有HierarchycalDataTemplate和包含子级的ObservableCollection的WPF TreeView

我正试图让这项工作，但不幸的是，我不知道我做错了什么！到目前为止，我已经研究了所有包含TreeView和HierarchycalDataTemplate的问题

问题是：我有一个树状视图，希望显示包含所有子文件夹和文件的文件夹结构。为此，我创建了一个包含必要项的类：

public class FolderItem : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    public void OnPropertyChanged(string propertyName)
    {
        var handler = PropertyChanged;

        if (handler != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
    public FolderItem()
    {
        Files = new ObservableCollection<FileItem>();
        SubFolders = new ObservableCollection<FolderItem>();
    }

    #region:PrivateVariables
    private DirectoryInfo _Info;
    private ObservableCollection<FileItem> _Files;
    private ObservableCollection<FolderItem> _SubFolders;
    #endregion

    public DirectoryInfo Info
    {
        get { return _Info; }
        set
        {
            _Info = value;
            OnPropertyChanged("Info");
        }
    }
    public ObservableCollection<FileItem> Files
    {
        get { return _Files; }
        set
        {
            _Files = value;
            OnPropertyChanged("Files");
        }
    }
    public ObservableCollection<FolderItem> SubFolders
    {
        get { return _SubFolders; }
        set
        {
            _SubFolders = value;
            OnPropertyChanged("SubFolders");
        }
    }
}
public class FileItem : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    public void OnPropertyChanged(string propertyName)
    {
        var handler = PropertyChanged;

        if (handler != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }

    #region:PrivateVariables
    private FileInfo _Info;
    #endregion

    public FileInfo Info
    {
        get { return _Info; }
        set
        {
            _Info = value;
            OnPropertyChanged("Info");
        }
    }
}

有了这个OC，我转到XAML并尝试了很多来显示数据：

    <TreeView ItemsSource="{Binding folders}">
    <TreeView.Resources>
        <HierarchicalDataTemplate ItemsSource="{Binding folders}" DataType="{x:Type local:FolderItem}">
            <HierarchicalDataTemplate.ItemTemplate>
                <DataTemplate>
                    <TextBlock Text="{Binding Info.Name}" />
                </DataTemplate>
            </HierarchicalDataTemplate.ItemTemplate>
        </HierarchicalDataTemplate>
    </TreeView.Resources>

    <TreeView.ItemContainerStyle>
        <Style TargetType="{x:Type TreeViewItem}">
            <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
        </Style>
    </TreeView.ItemContainerStyle>

    <TreeView.ItemTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding Info.FullName}" FontSize="16" FontWeight="Bold" />
        </DataTemplate>
    </TreeView.ItemTemplate>
</TreeView>

即使使用另一个HierarchycalDataTemplate，它也无法工作

我做错什么了吗？或者它只是不适用于可观察的集合

访谈还指出，在Visual Studio 2017更新后，出现了一个新的错误：作为Tpye“ViewModel_ZVLB”的“文件夹”，预期会出现一个instancemenber！（翻译自德语） 这和我的问题有关吗

---

谢谢你的帮助

在我看来，如果你想使用TreeView，只为孩子们使用一个Observablecollection比较容易

首先，我为树的每个元素创建一个泛型类。文件夹和文件类从中继承

public class TreeItem: INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    public void OnPropertyChanged(string propertyName)
    {
        var handler = PropertyChanged;

        if (handler != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

public class FolderItem:TreeItem
{
    public FolderItem()
    {
        Elems = new ObservableCollection<TreeItem>();
    }

    #region:PrivateVariables
    private DirectoryInfo _Info;
    private ObservableCollection<TreeItem> _Elems;
    #endregion

    public DirectoryInfo Info
    {
        get { return _Info; }
        set
        {
            _Info = value;
            OnPropertyChanged("Info");
        }
    }

    public ObservableCollection<TreeItem> Elems
    {
        get { return _Elems; }
        set
        {
            _Elems = value;
            OnPropertyChanged("Elems");
        }
    }
}
public class FileItem : TreeItem
{

    #region:PrivateVariables
    private FileInfo _Info;
    #endregion

    public FileInfo Info
    {
        get { return _Info; }
        set
        {
            _Info = value;
            OnPropertyChanged("Info");
        }
    }
}

public class TreeItem: INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    public void OnPropertyChanged(string propertyName)
    {
        var handler = PropertyChanged;

        if (handler != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

public class FolderItem:TreeItem
{
    public FolderItem()
    {
        Elems = new ObservableCollection<TreeItem>();
    }

    #region:PrivateVariables
    private DirectoryInfo _Info;
    private ObservableCollection<TreeItem> _Elems;
    #endregion

    public DirectoryInfo Info
    {
        get { return _Info; }
        set
        {
            _Info = value;
            OnPropertyChanged("Info");
        }
    }

    public ObservableCollection<TreeItem> Elems
    {
        get { return _Elems; }
        set
        {
            _Elems = value;
            OnPropertyChanged("Elems");
        }
    }
}
public class FileItem : TreeItem
{

    #region:PrivateVariables
    private FileInfo _Info;
    #endregion

    public FileInfo Info
    {
        get { return _Info; }
        set
        {
            _Info = value;
            OnPropertyChanged("Info");
        }
    }
}

    <TreeView ItemsSource="{Binding folders}">
        <TreeView.Resources>
            <HierarchicalDataTemplate ItemsSource="{Binding Elems}" DataType="{x:Type local:FolderItem}">
                <TextBlock Text="{Binding Info.Name}" FontWeight="Bold"/>
            </HierarchicalDataTemplate>
            <DataTemplate DataType="{x:Type local:FileItem}">
                <TextBlock Text="{Binding Info.Name}" />
            </DataTemplate>
        </TreeView.Resources>
    </TreeView>

    public void GetFileCount(string sPath, FolderItem actualFolder)
    {
        if (Directory.Exists(sPath))
        {
            foreach (string fileName in Directory.GetFiles(sPath))
            {
                FileItem newFile = new FileItem();
                newFile.Info = new FileInfo(fileName);
                actualFolder.Elems.Add(newFile);
            }

            foreach (string subFolder in Directory.GetDirectories(sPath))
            {
                FolderItem newSubFolder = new FolderItem();
                newSubFolder.Info = new DirectoryInfo(subFolder);
                actualFolder.Elems.Add(newSubFolder);

                GetFileCount(subFolder, newSubFolder);
            }
        }
    }