在treview MVVM中获取所选项目

Question

我尝试通过参考Josh的教程https://www.codeproject.com/Articles/26288/Simplifying-the-WPF-TreeView-by-Using-the-ViewMode将MVVM应用于树状视图>

这是我的完整源代码

TreeNode.cs

public class TreeNode
{
    private ObservableCollection<TreeNode> _children = new ObservableCollection<TreeNode>();

    public ObservableCollection<TreeNode> Children
    {
        get { return _children; }
        set { _children = value; }
    }

    public string Name { get; set; }

    public string ID { get; set; }

}
TreeNodeViewModel.cs

public class TreeNodeViewModel : INotifyPropertyChanged
{
    private ObservableCollection<TreeNodeViewModel> _children;
    private TreeNodeViewModel _seletected;
    private TreeNodeViewModel _parent;
    private TreeNode _node;

    bool _isExpanded;
    bool _isSelected;



    public TreeNodeViewModel(TreeNode node)
        : this(node, null)
    {
    }

    private TreeNodeViewModel(TreeNode node, TreeNodeViewModel parent)
    {
        _node = node;
        _parent = parent;

        _children = new ObservableCollection<TreeNodeViewModel>(
                (from child in _node.Children
                 select new TreeNodeViewModel(child, this))
                 .ToList<TreeNodeViewModel>());
    }

    public ObservableCollection<TreeNodeViewModel> Children
    {
        get { return _children; }
        set { _children = value; }
    }

    public string Name
    {
        get { return _node.Name; }
        set { _node.Name = value; }
    }
    public TreeNodeViewModel Selected
    {
        get { return _seletected; }
        set { _seletected = value; }
    }


    public bool IsExpanded
    {
        get { return _isExpanded; }
        set
        {
            if (value != _isExpanded)
            {
                _isExpanded = value;
                this.OnPropertyChanged("IsExpanded");
            }

            // Expand all the way up to the root.
            if (_isExpanded && _parent != null)
                _parent.IsExpanded = true;
        }
    }

    public bool IsSelected
    {
        get { return _isSelected; }
        set
        {
            if (value != _isSelected)
            {
                _isSelected = value;
                this.OnPropertyChanged("IsSelected");
                if (_isSelected) { _seletected = this; }
            }

        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    private void OnPropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}
TreeViewViewModel.cs

public class TreeViewViewModel
{
    readonly ObservableCollection<TreeNodeViewModel> _firstLevel;
    readonly TreeNodeViewModel _rootNode;

    private ICommand _addCommand;

    public TreeViewViewModel(TreeNode rootNode)
    {
        _rootNode = new TreeNodeViewModel(rootNode);

        _firstLevel = new ObservableCollection<TreeNodeViewModel>(_rootNode.Children);

        _addCommand = new AddCommand(this);
    }

    public ObservableCollection<TreeNodeViewModel> FirstLevel
    {
        get { return _firstLevel; }
    }

    public ICommand AddCommand
    {
        get { return _addCommand; }
    }
}
AddCommand.cs

public class AddCommand : ICommand
{
    private TreeViewViewModel _TreeView;

    public AddCommand(TreeViewViewModel treeView)
    {
        _TreeView = treeView;
    }

    public event EventHandler CanExecuteChanged;

    public bool CanExecute(object parameter)
    {
        return true;
    }

    public void Execute(object parameter)
    {
        //Show Selected item ????
        MessageBox.Show(_TreeView.????);




    }
}
我的目标是当我单击添加命令时，它将显示选定的项目名称和父级选定的项目名称。但是问题是TreeViewViewModel中没有任何东西可以访问TreeNodeViewModel。

这被中间类TreeViewViewModel阻止，它生活在Josh的世界中时无法访问TreeNodeViewModel的属性

我尝试通过参考Josh的教程https://www.codeproject.com/Articles/26288/Simplifying-the-WPF-TreeView-by-Using-the-ViewMode将MVVM应用到树视图中，这是我的完整源代码TreeNode .cs ...

Answer 1

根据我对您之前的问题的评论。将SelectedNode添加到TreeViewViewModel并将其设置在您的Node Selected setter中：

Answer 2

如果您担心应用程序的性能，则始终