Question

In a Windows App (Visual Studio)(VB) how do you drag and drop a single row to another postition to allow for the user to re-order the row? I haven’t found any worthy examples for this yet.

Answer 1

Here is a vb version from this C# answer: How could I Drag and Drop DataGridView Rows under each other?

The form class variables:

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

The drag events:

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

The mouse events:

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

Make sure you have the grids AllowDrop property set to true.