在DataGridView中拖放多列

Question

我有一个带有DataGridView的程序，我的用户希望能够在其中拖放多个列。

拖放单个列很容易，这是内置行为。但我找不到任何允许选择多个(相邻(列，然后将它们拖动到另一个列索引的设置。

有这样的设置吗？如果没有，以前有人这样做过吗？

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从已经收到的答案和评论来看，事情似乎朝着错误的方向发展，所以我想澄清问题是什么：

• 拖放一列不是问题，如上所述，我已经知道如何进行

• 拖放一行也不是问题。虽然与拖放列不同，但我知道如何做到这一点。

• 拖放多个列(或行(是个问题。。。

• 具体，如何选择多个列，然后启动DragDrop

在您真正尝试之前，不明显的是，为DragDrop选择单列(或行(的默认DataGridView UI语义无法用于拖放多列(或行将(这是我正在寻找的一个如何做的坚实的例子。我可能可以独自处理Drop完成的事情。这是多重选择和拖动启动的问题。

Answer 1

这应该是可能的。我这样做是为了在网格之间拖放行，所以同样的原则也应该适用。这不是一个解决方案，但它是一个构建块，希望它能让你开发一个。

首先，你需要处理鼠标移动事件，看看是否发生拖动：

AddHandler dgv.MouseMove, AddressOf CheckForDragDrop

这是我的CheckForDragDrop代码。您需要检查是否选择了列，以检测是否开始拖动。

Private Sub CheckForDragDrop(sender As Object, e As MouseEventArgs)
If e.Button = MouseButtons.Left Then
Dim ht As DataGridView.HitTestInfo = Me.HitTest(e.X, e.Y)
If (ht.Type = DataGridViewHitTestType.RowHeader OrElse ht.Type = DataGridViewHitTestType.Cell) AndAlso Me.Rows(ht.RowIndex).Selected Then
_ColumnDragInProgress = True
If Me.SelectedRows.Count > 1 Then
Me.DoDragDrop(Me.SelectedRows, DragDropEffects.All)
ElseIf Me.CurrentRow IsNot Nothing Then
Me.DoDragDrop(Me.CurrentRow, DragDropEffects.All)
End If
End If
End If
End Sub

您还需要处理DragEnter和DragDrop事件：

AddHandler dgv.DragEnter, AddressOf PerformDragEnter
AddHandler dgv.DragDrop, AddressOf PerformDragDrop

这是示例代码，但请记住，我在网格之间拖动行，而不是网格中的列：

Private Sub PerformDragEnter(sender As Object, e As DragEventArgs)
If e.Data.GetDataPresent(GetType(DataGridViewRow)) OrElse e.Data.GetDataPresent(GetType(DataGridViewSelectedRowCollection)) Then
e.Effect = DragDropEffects.Copy
End If
End Sub
Private Sub PerformDragDrop(sender As Object, e As DragEventArgs)
Dim dscreen As Point = New Point(e.X, e.Y)
Dim dclient As Point = Me.PointToClient(dscreen)
Dim HitTest As HitTestInfo = Me.HitTest(dclient.X, dclient.Y)
'If dropped onto an Existing Row, use that Row as Sender - otherwise Sender=This DGV.
If HitTest.RowIndex >= 0 Then _Dropped_RowHit = Me.Rows(HitTest.RowIndex) Else _Dropped_RowHit = Nothing
Dim DroppedRows As New List(Of DataGridViewRow)
If e.Data.GetDataPresent(GetType(DataGridViewRow)) Then
DroppedRows.Add(e.Data.GetData(GetType(DataGridViewRow)))
ElseIf e.Data.GetDataPresent(GetType(DataGridViewSelectedRowCollection)) Then
Dim Rows As DataGridViewSelectedRowCollection = e.Data.GetData(GetType(DataGridViewSelectedRowCollection))
For Each rw As DataGridViewRow In Rows
DroppedRows.Add(rw)
Next
Else
DroppedRows = Nothing
Exit Sub
End If
If DroppedRows(0).DataGridView Is Me Then Exit Sub
e.Data.SetData(DroppedRows)
_DraggedFrom_Name = DroppedRows(0).DataGridView.Name
'Drop occurred, add your code to handle it here
End Sub

我知道这并不能回答你提出的确切问题，但希望它能让你朝着正确的方向开始。

*更新*

再仔细想想，我相信这可能会更简单。

首先，创建自己的自定义DataGridView，它继承DataGridView如下：

Public Class CustomDGV
Inherits DataGridView

将DGV SelectionMode设置为DataGridViewSelectionMode.ColumnHeaderSelect或您希望允许列选择的任何模式

创建一些局部变量来跟踪拖动是否正在进行以及正在移动的内容，例如：

Dim ColDragInProgress as Boolean = False
Dim SelectedColumns as new List(Of Integer)

然后覆盖MouseDown和MouseUp事件以处理列拖动：

MouseDown事件需要测试您是否单击了选定的列。如果是这样的话，您可以拖动以标记并记录所有选定的列(以您喜欢的任何方式(：

Protected Overrides Sub OnMouseDown(e As MouseEventArgs)
If e.Button = MouseButtons.Left Then
Dim ht As DataGridView.HitTestInfo
ht = Me.HitTest(e.X, e.Y)
If ht.ColumnIndex>=0 AndAlso Me.Columns(ht.ColumnIndex).Selected Then
ColDragInProgress = True
SelectedColumns = StoreAllSelectedCols()
Else
ColDragInProgress = False
MyBase.OnMouseDown(e)
End If
Else
MyBase.OnMouseDown(e) 'in all other cases call the base function
End If
End Sub

然后处理MouseUp事件以查看是否真的发生了拖动。我假设如果你在一个未选中的列上鼠标悬停，它就会出现。当然，您可以只记录初始列，并检查鼠标是否在不同的列上，即使已选中。

Protected Overrides Sub OnMouseUp(ByVal e As MouseEventArgs)
If e.Button = Windows.Forms.MouseButtons.Right AndAlso ColDragInProgress Then
ColDragInProgress = False
Dim ht As DataGridView.HitTestInfo
ht = Me.HitTest(e.X, e.Y)
If ht.ColumnIndex>=0 AndAlso Not Me.Columns(ht.ColumnIndex).Selected Then  'On a Not selected Column so assume Drag Complete
Dim MoveToColumn As Integer = ht.ColumnIndex
PerformMovedColsToNewPosition(MoveToColumn, SelectedColumns)  'Your code to reorder cols as you want
Else
MyBase.OnMouseDown(e)
End If
Else
MyBase.OnMouseUp(e) 'now call the base Up-function
End If
End Sub

最后，您可以覆盖OnMouseMove，以便在拖动时显示正确的鼠标指针，如下所示：

Protected Overrides Sub OnMouseMove(e As System.Windows.Forms.MouseEventArgs)
If ColDragInProgress AndAlso e.Button = Windows.Forms.MouseButtons.Left  Then
Dim dropEffect As DragDropEffects = Me.DoDragDrop(SelectedColumns, DragDropEffects.Copy)
Else
MyBase.OnMouseMove(e) 'let's do the base class the rest
End If
End Sub

Answer 2

其他想法是使用OnColumnDisplayIndexChanged来查找所选列中的一列何时移动，记住之前所选列的位置。然后将它们放置在我们拖动的列的位置。在这种情况下，我们需要将选择模式从FullRow/Cell切换到column，但这只适用于排序模式DataGridViewColumnSortMode。编程可能会帮助您。默认键是"Alt"，用于在这种模式下拖放coumn

Dim newGrid As New MultiCollOrder
newGrid.Columns.Add("col_1", "col_1")
newGrid.Columns.Add("col_2", "col_2")
newGrid.Columns.Add("col_3", "col_3")
newGrid.Columns.Add("col_4", "col_4")
newGrid.Columns.Add("col_5", "col_5")
newGrid.Rows.Add({"1", "2", "3", "4", "5"})
newGrid.Rows.Add({"1a", "2a", "3a", "4a", "5a"})
newGrid.Rows.Add({"1b", "2b", "3b", "4b", "5b"})
newGrid.AllowUserToOrderColumns = True
Me.Controls.Add(newGrid)
newGrid.Dock = Windows.Forms.DockStyle.Fill
Public Class MultiCollOrder
Inherits System.Windows.Forms.DataGridView
Private _NewOrder As List(Of Integer) 'New Order
Private _orgSelectedOrder As New List(Of Integer) 'orginal order
Protected Overrides Sub OnCellClick(e As DataGridViewCellEventArgs)
If e.RowIndex >= 0 Then
'for rows
Me.SelectionMode = DataGridViewSelectionMode.FullRowSelect
For Each ecol As DataGridViewColumn In Me.Columns
ecol.SortMode = DataGridViewColumnSortMode.Automatic
Next
Else
'for column
_orgSelectedOrder.Clear() '
For Each ecol As DataGridViewColumn In (From esor As DataGridViewColumn In Me.SelectedColumns Order By esor.DisplayIndex Ascending)
_orgSelectedOrder.Add(ecol.Index)
Next
End If
MyBase.OnCellClick(e)
End Sub
Protected Overrides Sub OnColumnHeaderMouseClick(e As DataGridViewCellMouseEventArgs)
For Each ecol As DataGridViewColumn In Me.Columns
ecol.SortMode = DataGridViewColumnSortMode.Programmatic
Next
Me.SelectionMode = DataGridViewSelectionMode.ColumnHeaderSelect
MyBase.OnColumnHeaderMouseClick(e)
End Sub
Protected Overrides Sub OnColumnDisplayIndexChanged(e As DataGridViewColumnEventArgs)
If Me.SelectedColumns.Count > 1 And e.Column.Selected And _NewOrder Is Nothing Then
_NewOrder = New List(Of Integer)
For Each ec As DataGridViewColumn In (From esor As DataGridViewColumn In Me.Columns Order By esor.DisplayIndex Ascending)
If ec.Index = e.Column.Index Then
For Each esc In _orgSelectedOrder
_NewOrder.Add(esc)
Next
Else
If ec.Selected = False Then _NewOrder.Add(ec.Index)
End If
Next
End If
MyBase.OnColumnDisplayIndexChanged(e)
End Sub
Protected Overrides Sub OnPaint(e As PaintEventArgs)
If Not _NewOrder Is Nothing Then ' Apply New order
For x As Integer = 0 To _NewOrder.Count - 1
Me.Columns(_NewOrder(x)).Selected = False
Me.Columns(_NewOrder(x)).DisplayIndex = x
Next
_NewOrder = Nothing
End If
MyBase.OnPaint(e)
End Sub
End Class

Answer 3

为DataGridView编程UI的方式不支持直观的方法，因为如果在选择内部左键单击，它会更改选择。

您最好的选择可能是在DataGridView.CellMouseDown事件中选中e.Button以进行右键或中键单击。然后，您可以访问.SelectedCells属性来存储列选择，然后在DataGridView.CellMouseUp事件中执行"drop"操作。