拖放功能

关于拖放，可以通过以下博客对拖放之间的事件关系进行了解
http://www.cnblogs.com/loveis715/archive/2011/12/05/2277384.html

拖放的公用类库 Platform.Common中的DragAndDrop，其中
DragDropAdorner用来显示被拖拽的界面元素的预览
Win32：用于返回鼠标位置
Utils：获取拖放的项

以上直接引用即可，具体拖放的实现要根据【拖拽源】和【拖拽目标】的不同以及值的不同处理而自行编写

以下为将TreeView子项拖放到ListBox中的示例

XML中

【拖放源】
1.设置属性AllowDrop="True"
<TreeView x:Name="DragTreeSource" ItemsSource="{Binding OcComDepRoleTree}"
BorderThickness="0" Background="#D3E2C5" Margin="10,5,0,5"
ItemTemplate="{StaticResource ItemNode}"
HorizontalAlignment="Left" Width="200"
AllowDrop="True">
</TreeView>
2.添加事件TreeViewItem事件
<Style TargetType="TreeViewItem">
<EventSetter Event="TreeViewItem.PreviewMouseMove" Handler="OnPreviewListBoxMouseMove"/>
<EventSetter Event="TreeViewItem.QueryContinueDrag" Handler="OnQueryContinueDrag"/>
</Style>
note:此时的TreeView的Style不能设置为静态的资源了，样式什么的都要自己写进来，以上省去为了突出事件

【拖放目标】
1.设置属性AllowDrop="True"；
2.绑定事件命令 DragDrop.DragOver="OnSignDragOver" DragDrop.Drop="OnSignDrop"
<ListBox x:Name="lstSign" Background="#D3E2C5"
AllowDrop="True"
DragDrop.DragOver="OnSignDragOver" DragDrop.Drop="OnSignDrop"
ItemsSource="{Binding OcDepForSign, Mode=TwoWay}" />

CS 中
AdornerLayer mAdornerLayer = null; //装饰器
【拖放源】
private void OnQueryContinueDrag(object sender, QueryContinueDragEventArgs e)
{
mAdornerLayer.Update();
}
private void OnPreviewListBoxMouseMove(object sender, MouseEventArgs e)
{
if (Mouse.LeftButton != MouseButtonState.Pressed)
return;

Point pos = e.GetPosition(DragTreeSource);
HitTestResult result = VisualTreeHelper.HitTest(DragTreeSource, pos);
if (result == null)
return;

TreeViewItem treeItem = Utils.FindVisualParent<TreeViewItem>(result.VisualHit); // Find your actual visual you want to drag
if (treeItem == null || treeItem.DataContext != DragTreeSource.SelectedItem || !(DragTreeSource.SelectedItem is BaseTreeModel))
return;

DragDropAdorner adorner = new DragDropAdorner(treeItem); //(DragDropAdorner实现Adorner抽象类)

mAdornerLayer = AdornerLayer.GetAdornerLayer(DragTreeSource);

mAdornerLayer.Add(adorner);

BaseTreeModel dataItem = treeItem.DataContext as BaseTreeModel;

DataObject dob = new DataObject(dataItem);

DragDrop.DoDragDrop(DragTreeSource, dob, DragDropEffects.Copy);//启动拖拽

mAdornerLayer.Remove(adorner);
}

【拖放目标】

private void OnSignDragOver(object sender, DragEventArgs e)
{
OnDragOver(e,lstSign);
}
private void OnSignDrop(object sender, DragEventArgs e)
{
OnDrag(e, lstSign);
}

private void OnDrag(DragEventArgs e ,ListBox lst)
{
try
{
Point pos = e.GetPosition(lst);
HitTestResult result = VisualTreeHelper.HitTest(lst, pos);
if (result == null)
return;
//获取拖放数据
BaseTreeModel dataItdem = e.Data.GetData(typeof(BaseTreeModel)) as BaseTreeModel;
//数据处理

}
catch (Exception ex)
{
throw ex;
}
}
private void OnDragOver(DragEventArgs e,ListBox lst)
{
e.Effects = DragDropEffects.None;

Point pos = e.GetPosition(lst);
HitTestResult result = VisualTreeHelper.HitTest(lst, pos);
if (result == null)
return;

ListBoxItem selectedItem = Utils.FindVisualParent<ListBoxItem>(result.VisualHit);
if (selectedItem != null)
selectedItem.IsSelected = true;
e.Effects = DragDropEffects.Copy;
}