为什么调用 TreeView.ItemContainerGenerator.ContainerFromItem(...)总是返回 null ？
我定义了一个类ArchiveGroup_Node, 然后生成了一个集合ObservableCollection<ArchiveGroup_Node> mydata并填充的数据，然后绑定到TreeView.ItemsSource=mydata,显示结果很正常，但是当我调用TreeView.ItemContainerGenerator.ContainerFromItem(mydata[0].Children[0]) 时总是返回空值“null”，但是调用TreeView.ItemContainerGenerator.ContainerFromItem(mydata[0]) 却可以正常的返回TreeViewItem类型的容器，也就是说只有数据集的根节点可以正常的返回与之对应的容器，而子节点却无法利用TreeView.ItemContainerGenerator.ContainerFromItem返回与之相关的容器，不知道是哪里做错了？
public class ArchiveGroup_Node : INotifyPropertyChanged
{
public ArchiveGroup_Node()
{
Children=new ObservableCollection<ArchiveGroup_Node> ();
}
private ArchiveGroup_Node _meparent = null;
public ObservableCollection<ArchiveGroup_Node> Children
{get; set;}
public ArchiveGroup_Node Parent
{
get { return _meparent; }
set { _meparent = value; }
}
private int _id;
private int _a_parentid;
private string _a_name;
private string _a_detail;
private bool _a_isdel;
private int _r_w;
private string _a_value;
//----------------------------------------------------------------------
public int id { get { return _id; } set { _id = value; NotifyPropertyChanged("id"); } }
public int a_parentid { get { return _a_parentid; } set { _a_parentid = value; NotifyPropertyChanged("a_parentid"); } }
public string a_name { get { return _a_name; } set { _a_name = value; NotifyPropertyChanged("a_name"); } }
public string a_value { get { return _a_value; } set { _a_value = value; NotifyPropertyChanged("a_value"); } }
public string a_detail { get { return _a_detail; } set { _a_detail = value; NotifyPropertyChanged("a_detail"); } }
public bool a_isdel { get { return _a_isdel; } set { _a_isdel = value; NotifyPropertyChanged("a_isdel"); } }
public int r_w { get { return _r_w; } set { _r_w = value; NotifyPropertyChanged("r_w"); } }
//-------------------------------------------
public event PropertyChangedEventHandler PropertyChanged;
public void NotifyPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
XAML部分
<controls:TreeView x:Name="ArchiveGroup" Grid.Column="0" SelectedItemChanged="ArchiveGroup_SelectedItemChanged" >
<controls:TreeView.ItemTemplate>
<common:HierarchicalDataTemplate ItemsSource="{Binding Children}">
<StackPanel Orientation="Horizontal" Tag="{Binding a_detail}">
<TextBlock Text="{Binding a_name}" />
</StackPanel>
</common:HierarchicalDataTemplate>
</controls:TreeView.ItemTemplate>
</controls:TreeView>
