拖放对象参考VB.Net [英] Drag and Dropping an Object Reference VB.Net

问题描述

我正在尝试交换两个单元格的内容及其映射。为此，我需要将对单元格的引用拖放到字符串值本身。然后，我可以使用此引用来更新字典以及获取值。它允许我进行交换，因为我将引用旧单元格以在其中添加所需的值。

I am trying to 'swap' two cells' contents, and their mappings. To do this, I need to drag and drop a reference to the cell as opposed to the string value itself. I can then use this reference to update a Dictionary as well as get the value. It allows allows me to do the swap as I will have a reference to the old cell to add the value needed in there.

我遇到的问题是我不是确保如何传递单元格引用：

The problem I am having is I am not sure how to pass the cell reference:

Private Sub DataGridView1_MouseDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles DataGridView1.MouseDown
    If e.Button = MouseButtons.Left Then
        DataGridView1.DoDragDrop(DataGridView1.CurrentCell, DragDropEffects.Copy)
    End If

End Sub

并在放置事件中：

Private Sub DataGridView1_DragDrop(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles DataGridView1.DragDrop

   'Problem is here -->'Dim copyedFromCell As DataGridViewCell = DirectCast(e.Data(), DataGridViewCell)** 
    Dim copyedFromKey As String = GetMappingForCell(copyedFromCell) 
    Dim thisKey As String = GetMappingForCell(DataGridView1.CurrentCell)
    Dim copyedFromValue As String = copyedFromCell.Value
    Dim thisValue As String = DataGridView1.CurrentCell.Value

    mappings(copyedFromKey) = DataGridView1.CurrentCell
    mappings(thisKey) = copyedFromCell

    DataGridView1.CurrentCell.Value = copyedFromValue
    copyedFromCell.Value = thisValue

End Sub

我想做的是可能的吗？我已经完全打破了吗？谢谢：）

Is what I am trying to do possible? Have I completely broken it? Thanks :)

推荐答案

您的 e.Data 是 IDataObject ，不通过 DoDragDrop 发送的值。

Your e.Data is a IDataObject, not the value you sent with DoDragDrop.

要获取发送的值，必须致电 e.Data.GetData（...） 。

To get the value you sent, you must call e.Data.GetData(...).

要修复您的代码，请将问题行替换为：

To fix your code, replace the problem line with:

Dim copiedFromCell As DataGridViewCell = _
   e.Data.GetData(GetType(DataGridViewTextBoxCell))

（或 DataGridView1.CurrentCell的任何类型是。）

您可以通过调用 e.Data.GetFormats（） 。

You can get a list of types available to be dropped by calling e.Data.GetFormats().

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