WPF拖放自定义类

Posted 2021-04-20

我开始这样的操作：

Public Sub cLinkOut_MouseDown(ByVal sender As Object, ByVal e As MouseEventArgs)
    'Trace.WriteLine("mousedown: " & ObjectKey)
    DragDrop.DoDragDrop(TryCast(Me, CellContainer), ObjectKey, DragDropEffects.All)
    e.Handled = True
End Sub

“Me”是一个名为CellContainer的自定义类，它实际上是一个具有附加属性的画布。

我像这样处理掉落：

Public Sub cLinkIn_Drop(ByVal sender As Object, ByVal e As DragEventArgs)
    Dim cSource As String = e.Data.GetData(DataFormats.StringFormat)
    Dim cTarget As String = TryCast(e.OriginalSource, CellContainer).ObjectKey
    Trace.WriteLine("srce: " & cSource & ", targ: " & cTarget)
    e.Handled = True
End Sub

问题是e.OriginalSource显示为Canvas，而不是CellContainer，并且cTarget设置为Nothing。如何将整个CellContainer（不仅仅是ObjectKey）从Drag拖放到Drop？

答案

解决它像这样：

Public Sub cLinkOut_MouseDown(ByVal sender As Object, ByVal e As MouseEventArgs)
    Dim data As DataObject = New DataObject(DataFormats.Serializable, Me)
    DragDrop.DoDragDrop(CType(e.Source, DependencyObject), data, DragDropEffects.Copy)
    e.Handled = True
End Sub

Public Sub cLinkIn_Drop(ByVal sender As Object, ByVal e As DragEventArgs)
    Dim c As CellContainer = CType(e.Data.GetData(DataFormats.Serializable), CellContainer)
    Dim cSource As String = c.ObjectKey
    Dim cTarget As String = Me.ObjectKey
    Trace.WriteLine("srce: " & cSource & ", targ: " & cTarget)
    e.Handled = True
End Sub