C# WPF视图模型问题

我有一个用于树视图的递归视图模型。问题是每次我删除组项或条目项时。在我通过treeview.Items.Refresh（）强制更改之前，treeview无法立即反映更改。我猜可观察到的收集项目确实得到了通知。你能给我指一个吗。谢谢

视图模型

public class Group:ViewModelBase
{
    private int _key;

    public int Key
    {
        get { return _key; }
        set { _key = value; OnPropertyChanged("Key"); }
    }
    private string _name;

    public string Name
    {
        get { return _name; }
        set { _name = value; OnPropertyChanged("Name"); }
    }
    private bool _isexpanded;

    public bool IsExpanded
    {
        get { return _isexpanded; }
        set { _isexpanded = value; OnPropertyChanged("IsExpanded"); }
    }
    private int _order;

    public int Order
    {
        get { return _order; }
        set { _order = value; OnPropertyChanged("Order"); }
    }
    private int _grouporder;

    public int GroupOrder
    {
        get { return _grouporder; }
        set { _grouporder = value; OnPropertyChanged("GroupOrder"); }
    }
    private string _error;

    public string Error
    {
        get { return _error; }
        set { _error = value; OnPropertyChanged("Error"); }
    }
    private ObservableCollection<Group> _subgroups;

    public ObservableCollection<Group> SubGroups
    {
        get { return _subgroups; }
        set { _subgroups = value; 
            OnPropertyChanged("SubGroups");
            OnPropertyChanged("Entries");
        }
    }
    private ObservableCollection<Entry> _entries;

    public ObservableCollection<Entry> Entries
    {
        get { return _entries; }
        set { _entries = value;
            OnPropertyChanged("SubGroups");
            OnPropertyChanged("Entries"); }
    }


    public ObservableCollection<object> Items
    {
        get
        {
            ObservableCollection<object> childNodes = new ObservableCollection<object>();
            foreach (var entry in this.Entries)
                childNodes.Add(entry);
            foreach (var group in this.SubGroups)
                childNodes.Add(group);
            return childNodes;
        }

    }
}

---

问题是，您断开了与原始集合的链接

因此，我可以想象两种解决方案：

1） 注册

条目

和

子组

的更改，并将其应用回

项目

：

private ObservableCollection<object> items;
public ObservableCollection<object> Items
{
    get
    {
        if (items == null)
        {
            items = new ObservableCollection<object>();
            foreach (var entry in this.Entries)
                items.Add(entry);
            foreach (var group in this.SubGroups)
                items.Add(group);


            this.Entries.CollectionChanged += (s, a) =>
            {
                if (/*add some stuff*/)
                {
                    items.Add(/*some stuff*/)
                }
                else if (/*remove some stuff*/)
                {
                    items.Remove(...)
                }
            };

            this.SubGroups.CollectionChanged += ...

            return items;
        }
    }
}

---

不确定第二种解决方案是否可行，但它将非常优雅，值得一试……

对。永远不要设置ObservableCollection属性，始终调用Clear（）和Add（），否则将覆盖绑定信息。@Pragmateek，谢谢！！你救了我一天。我参加了作文集锦！！

private ObservableCollection<object> items;
public ObservableCollection<object> Items
{
    get
    {
        if (items == null)
        {
            items = new ObservableCollection<object>();
            foreach (var entry in this.Entries)
                items.Add(entry);
            foreach (var group in this.SubGroups)
                items.Add(group);


            this.Entries.CollectionChanged += (s, a) =>
            {
                if (/*add some stuff*/)
                {
                    items.Add(/*some stuff*/)
                }
                else if (/*remove some stuff*/)
                {
                    items.Remove(...)
                }
            };

            this.SubGroups.CollectionChanged += ...

            return items;
        }
    }
}

new CompositeCollection
{
    new CollectionContainer { Collection = this.Entries },
    new CollectionContainer { Collection = this.SubGroups }
};