如何在同一个datagridview中拖放行答案

【问题标题】：How to drag and drop row within the same datagridview如何在同一个datagridview中拖放行
【发布时间】：2012-07-18 23:40:38
【问题描述】：

在 Windows 应用程序 (Visual Studio)(VB) 中，如何将单行拖放到另一个位置以允许用户重新排序该行？我还没有找到任何有价值的例子。

【问题讨论】：

标签： vb.net visual-studio-2010 datagridview drag-and-drop datagridviewrow

【解决方案1】：

这是来自这个 C# 答案的 vb 版本：How could I Drag and Drop DataGridView Rows under each other?

表单类变量：

Private fromIndex As Integer
Private dragIndex As Integer
Private dragRect As Rectangle

拖动事件：

Private Sub DataGridView1_DragDrop(ByVal sender As Object, _
                                   ByVal e As DragEventArgs) _
                                   Handles DataGridView1.DragDrop
  Dim p As Point = DataGridView1.PointToClient(New Point(e.X, e.Y))
  dragIndex = DataGridView1.HitTest(p.X, p.Y).RowIndex
  If (e.Effect = DragDropEffects.Move) Then
    Dim dragRow As DataGridViewRow = e.Data.GetData(GetType(DataGridViewRow))
    DataGridView1.Rows.RemoveAt(fromIndex)
    DataGridView1.Rows.Insert(dragIndex, dragRow)
  End If
End Sub

Private Sub DataGridView1_DragOver(ByVal sender As Object, _
                                   ByVal e As DragEventArgs) _
                                   Handles DataGridView1.DragOver
  e.Effect = DragDropEffects.Move
End Sub

鼠标事件：

Private Sub DataGridView1_MouseDown(ByVal sender As Object, _
                                    ByVal e As MouseEventArgs) _
                                    Handles DataGridView1.MouseDown
  fromIndex = DataGridView1.HitTest(e.X, e.Y).RowIndex
  If fromIndex > -1 Then
    Dim dragSize As Size = SystemInformation.DragSize
    dragRect = New Rectangle(New Point(e.X - (dragSize.Width / 2), _
                                       e.Y - (dragSize.Height / 2)), _
                             dragSize)
  Else
    dragRect = Rectangle.Empty
  End If
End Sub

Private Sub DataGridView1_MouseMove(ByVal sender As Object, _
                                    ByVal e As MouseEventArgs) _
                                    Handles DataGridView1.MouseMove
  If (e.Button And MouseButtons.Left) = MouseButtons.Left Then
    If (dragRect <> Rectangle.Empty _
    AndAlso Not dragRect.Contains(e.X, e.Y)) Then
      DataGridView1.DoDragDrop(DataGridView1.Rows(fromIndex), _
                               DragDropEffects.Move)
    End If
  End If
End Sub

确保将 grids AllowDrop 属性设置为 true。

【讨论】：

有人能回答为什么我在 Datagridview 中拖动一行时会出现这些错误吗？ Rows cannot be programmatically added to the DataGridView's rows collection when the control is data-bound.
@ChadPatrick 就像错误所说的那样，您的网格是数据绑定的（您有一个数据源），这意味着您不能直接操作网格。在您的情况下，您需要操作数据源。如果您有问题，请发布一个新问题并适当记录。
我该如何操作数据源？这是我填充数据网格视图的代码：con = New SqlConnection con.ConnectionString = "Data Source=mssql;Initial Catalog=DATABASE;User ID=sa;Password=" con.Open() adap = New SqlDataAdapter("SELECT * FROM tablename", con) ds = New System.Data.DataSet() adap.Fill(ds, "TableNew") Datagridview1.DataSource = ds.Tables(0) con.Close()
@ChadPatrick 您的数据表：ds.Tables(0)。如果您在该数据表中添加一行，您的网格将自动显示它。

【解决方案2】：

更新：

代替

 If dragIndex < 0 Then dragIndex = DataGridView1.RowCount - 1

改成

 If dragIndex > -1 Then 
      'action if not selected in the row header and blank space
 else
      'return error if selected in the column header and blank space
 end if

那么当你将一行拖到“空白区”时就会出错，不信你一定要试试。

最终代码（仅适用于“拖动事件”部分）是这样的：

  Private Sub DataGridView1_DragDrop(ByVal sender As Object, ByVal e As DragEventArgs) Handles DataGridView1.DragDrop
        Dim p As Point = DataGridView1.PointToClient(New Point(e.X, e.Y))
        dragIndex = DataGridView1.HitTest(p.X, p.Y).RowIndex
    'Determine if dragindex is valid row index       
    If dragIndex > -1 Then
        If (e.Effect = DragDropEffects.Move) Then
            Dim dragRow As DataGridViewRow = CType(e.Data.GetData(GetType(DataGridViewRow)), DataGridViewRow)
            DataGridView1.Rows.RemoveAt(fromIndex)
            DataGridView1.Rows.Insert(dragIndex, dragRow)
            'Add this line of code if you want to put selected rows to the rows that change
            DataGridView1.Rows(dragIndex).Selected = True
        End If 
       Else 'Do any message here if selected in column header and blank space. 
       End If
    End Sub

【讨论】：

【解决方案3】：

感谢您所做的一切，代码工作正常。我只得到一个错误。我解决了。

如果设置了datagridview“启用编辑”，则在抛出行距时会收到错误消息。你可以试试。我解决了如下：

    Private Sub DataGridView1(ByVal sender As Object, ByVal e As DragEventArgs) Handles DataGridView1.DragDrop

    Dim p As Point = DataGridView1.PointToClient(New Point(e.X, e.Y))
                    dragIndex = DataGridView1.HitTest(p.X, p.Y).RowIndex
                    If (e.Effect = DragDropEffects.Move) Then
                        Dim dragRow As DataGridViewRow = CType(e.Data.GetData(GetType(DataGridViewRow)), DataGridViewRow)

                        If dragIndex = DataGridView1.RowCount - 1 Then '**ADD THIS AREA**
                            DataGridView1.Rows.RemoveAt(fromIndex)
                            DataGridView1.Rows.Insert(DataGridView1.RowCount - 1, dragRow)
                        Else
                            If dragIndex < 0 Then dragIndex = DataGridView1.RowCount - 2 '**this is important**
                            DataGridView1.Rows.RemoveAt(fromIndex)
                            DataGridView1.Rows.Insert(dragIndex, dragRow)
                        End If
                    End If
End Sub

感谢您提供所有其他信息

【讨论】：

【解决方案4】：

这是一个没有上述错误的控件。

在 Windows 窗体设计器中将 AllowUserToOrderRows 和 AllowDrop 设置为 True，然后拖动行标题，而不是内容。

Imports System.ComponentModel

Public Class BetterDataGridView
    Inherits DataGridView

    <Category("Behavior"), DefaultValue(False)>
    Public Property AllowUserToOrderRows As Boolean = False

    Protected Overrides Sub OnMouseDown(e As MouseEventArgs)
        MyBase.OnMouseDown(e)

        Dim hitInfo As HitTestInfo = HitTest(e.X, e.Y)
        If AllowUserToOrderRows AndAlso
                e.Button = MouseButtons.Left AndAlso
                hitInfo.ColumnIndex = -1 AndAlso
                ValidRow(hitInfo.RowIndex) Then
            DoDragDrop(Rows(hitInfo.RowIndex), DragDropEffects.Move)
        End If
    End Sub

    Protected Overrides Sub OnDragOver(e As DragEventArgs)
        MyBase.OnDragOver(e)

        Dim dragRow As DataGridViewRow = e.Data.GetData(GetType(DataGridViewRow))
        Dim targetIndex As Integer = GetRowIndex(e)
        e.Effect = If(ValidRowDragDrop(dragRow, targetIndex),
                      DragDropEffects.Move,
                      DragDropEffects.None)
    End Sub

    Protected Overrides Sub OnDragDrop(e As DragEventArgs)
        MyBase.OnDragDrop(e)

        Dim dragRow As DataGridViewRow = e.Data.GetData(GetType(DataGridViewRow))
        Dim targetIndex As Integer = GetRowIndex(e)

        If e.Effect = DragDropEffects.Move AndAlso ValidRowDragDrop(dragRow, targetIndex) Then
            EndEdit()

            Rows.Remove(dragRow)
            Rows.Insert(targetIndex, dragRow)

            ClearSelection()
            dragRow.Selected = True
        End If
    End Sub

    Protected Function ValidRow(rowIndex As Integer) As Boolean
        Return rowIndex >= 0 AndAlso
            rowIndex < Rows.Count - If(AllowUserToAddRows, 1, 0)
    End Function

    Protected Function GetRowIndex(e As DragEventArgs) As Integer
        Dim clientPos As Point = PointToClient(New Point(e.X, e.Y))
        Return HitTest(clientPos.X, clientPos.Y).RowIndex
    End Function

    Protected Function ValidRowDragDrop(dragRow As DataGridViewRow, targetIndex As Integer) As Boolean
        Return dragRow IsNot Nothing AndAlso
            ValidRow(targetIndex) AndAlso
            targetIndex <> dragRow.Index AndAlso
            Rows.Contains(dragRow)
    End Function
End Class

【讨论】：

注意：该控件只有在您成功构建项目后才会出现在工具箱中。
我还发现，如果我扩展一些 WinForms 控件，那么新代码必须编译为 32 位才能工作（因此只能在工具箱中看到成功编译为32 位）。详情请见stackoverflow.com/a/26539992/1624894。

【解决方案5】：

1.5 事件改进GridView.DragDrop：

前50%的改进，为了避免描述的错误你也可以使用

Private Sub DgvSearchFieldCurrent_DragDrop( _
   ByVal sender As  Object, ByVal e As DragEventArgs) _
   Handles DgvSearchFieldCurrent.DragDrop

Dim LclDgv As DataGridView = CType(sender, DataGridView)

If dragIndex > -1 AndAlso dragIndex < LclDgv.RowCount -1 Then

二是设置焦点到当前行和第一个单元格：

LclDgv.Rows.Insert(dragIndex, dragRow)

LclDgv.Rows(fromIndex).Selected = False
LclDgv.Rows(dragIndex).Selected = True

For Each C As DataGridViewColumn In LclDgv.Columns
  LclDgv(C.Index, fromIndex).Selected = False
Next

LclDgv(0, dragIndex).Selected = True

【讨论】：