我在TreeView中的WPF中拖放存在问题。 拖放的作品，但不是我想要的。
我的自定义类是PhonesFromStudents
public class PhonesFromStudents
{
public string Name { get; set; }
public List<string> Phones { get; set; }
}
构造函数：
internal MainWindow(List<PhonesFromStudents> list)
{
InitializeComponent();
this.ListStudents = list;
this.DataContext = this;
}
这是我的拖放代码：
private void treeView_MouseMove(object sender, MouseEventArgs e)
{
try
{
if (e.LeftButton == MouseButtonState.Pressed)
{
Point currentPosition = e.GetPosition(tv_source);
if ((Math.Abs(currentPosition.X - _lastMouseDown.X) > 10.0) ||
(Math.Abs(currentPosition.Y - _lastMouseDown.Y) > 10.0))
{
draggedItem = (TreeViewItem)(TreeViewItem)sender;
if (draggedItem != null)
{
DragDropEffects finalDropEffect = DragDrop.DoDragDrop(tv_source, tv_source.SelectedValue, DragDropEffects.Move);
//Checking target is not null and item is dragging(moving)
if ((finalDropEffect == DragDropEffects.Move) && (_target != null))
{
// A Move drop was accepted
if (!draggedItem.Header.ToString().Equals(_target.Header.ToString()))
{
CopyItem(draggedItem, _target);
_target = null;
draggedItem = null;
}
}
}
}
}
}
catch (Exception)
{
}
}
private void treeView_DragOver(object sender, DragEventArgs e)
{
try
{
Point currentPosition = e.GetPosition(tv_source);
if ((Math.Abs(currentPosition.X - _lastMouseDown.X) > 10.0) ||
(Math.Abs(currentPosition.Y - _lastMouseDown.Y) > 10.0))
{
// Verify that this is a valid drop and then store the drop target
TreeViewItem item = GetNearestContainer(e.OriginalSource as UIElement);
if (CheckDropTarget(draggedItem, item))
{
e.Effects = DragDropEffects.Move;
}
else
{
e.Effects = DragDropEffects.None;
}
}
e.Handled = true;
}
catch (Exception)
{
}
}
private void treeView_Drop(object sender, DragEventArgs e)
{
try
{
e.Effects = DragDropEffects.None;
e.Handled = true;
// Verify that this is a valid drop and then store the drop target
TreeViewItem TargetItem = GetNearestContainer(e.OriginalSource as UIElement);
if (TargetItem != null && draggedItem != null)
{
_target = TargetItem;
e.Effects = DragDropEffects.Move;
}
}
catch (Exception)
{
}
}
private bool CheckDropTarget(TreeViewItem _sourceItem, TreeViewItem _targetItem)
{
//Check whether the target item is meeting your condition
bool _isEqual = false;
if (!_sourceItem.Header.ToString().Equals(_targetItem.Header.ToString()))
{
_isEqual = true;
}
return _isEqual;
}
private void CopyItem(TreeViewItem _sourceItem, TreeViewItem _targetItem)
{
//Asking user wether he want to drop the dragged TreeViewItem here or not
if (MessageBox.Show("Would you like to drop " + _sourceItem.Header.ToString() + " into " + _targetItem.Header.ToString() + "", "", MessageBoxButton.YesNo) == MessageBoxResult.Yes)
{
try
{
//adding dragged TreeViewItem in target TreeViewItem
addChild(_sourceItem, _targetItem);
//finding Parent TreeViewItem of dragged TreeViewItem
TreeViewItem ParentItem = FindVisualParent<TreeViewItem>(_sourceItem);
// if parent is null then remove from TreeView else remove from Parent TreeViewItem
if (ParentItem == null)
{
tv_source.Items.Remove(_sourceItem);
}
else
{
ParentItem.Items.Remove(_sourceItem);
}
}
catch
{
}
}
}
public void addChild(TreeViewItem _sourceItem, TreeViewItem _targetItem)
{
// add item in target TreeViewItem
TreeViewItem item1 = new TreeViewItem();
item1.Header = _sourceItem.Header;
_targetItem.Items.Add(item1);
foreach (TreeViewItem item in _sourceItem.Items)
{
addChild(item, item1);
}
}
static TObject FindVisualParent<TObject>(UIElement child) where TObject : UIElement
{
if (child == null)
{
return null;
}
UIElement parent = VisualTreeHelper.GetParent(child) as UIElement;
while (parent != null)
{
TObject found = parent as TObject;
if (found != null)
{
return found;
}
else
{
parent = VisualTreeHelper.GetParent(parent) as UIElement;
}
}
return null;
}
private TreeViewItem GetNearestContainer(UIElement element)
{
// Walk up the element tree to the nearest tree view item.
TreeViewItem container = element as TreeViewItem;
while ((container == null) && (element != null))
{
element = VisualTreeHelper.GetParent(element) as UIElement;
container = element as TreeViewItem;
}
return container;
}
我的XAML：
<TreeView x:Name="tv_source" AllowDrop="True" Grid.Row="2" Grid.Column="1" Margin="0,5" HorizontalAlignment="Stretch" ItemsSource="{Binding list}" Background="White" BorderBrush="{x:Null}">
<TreeView.ItemContainerStyle>
<Style TargetType="{x:Type TreeViewItem}">
<!-- We have to select the item which is right-clicked on -->
<!--<EventSetter Event="TreeViewItem.PreviewMouseRightButtonDown" Handler="TreeViewItem_PreviewMouseRightButtonDown"/>-->
<EventSetter Event="PreviewDragOver" Handler="treeView_DragOver"/>
<EventSetter Event="PreviewDrop" Handler="treeView_Drop"/>
<EventSetter Event="TreeViewItem.MouseMove" Handler="treeView_MouseMove"/>
</Style>
</TreeView.ItemContainerStyle>
<TreeView.Resources>
<HierarchicalDataTemplate DataType="{x:Type local:PhonesFromStudents}" ItemsSource="{Binding Phones}">
<TextBlock Text="{Binding Name}" AllowDrop="True" />
</HierarchicalDataTemplate>
</TreeView.Resources>
</TreeView>
我的问题是，它只会在孩子身上添加一个孩子，而不是在父母身上，这对我不利。
示例：
Thomas
|_____iPhone8
|_____iPhone6
Lucas
|_____iPhone4s
|_____S8
如果我将“ iPhone8”移至“ Lucas”，则无法使用，仅当我将iPhone8移至“ iPhone4s”或“ S8”时，该功能才起作用。
我想要什么：
Thomas
|_____iPhone8
|_____iPhone6
|_____S8
Lucas
|_____iPhone4s
我有什么
Thomas
|_____iPhone8
|_____iPhone6
|_____S8
Lucas
|_____iPhone4s