Move up or down little complex DataGridView rows with multi-selection

Question

I have a DataGridView like this:

enter image description here

Now, In C# or else VB.Net, with a button, I would like to move up or down one position the selected rows, how I could do it?. The multi selection requisite complicate me this.

The files that appear in the DataGridView will be combined into a single executable file, then, the files will be executed in the order of the "Order" column, so the "Order" value should be inmutable when moving rows up or down.

I'm not using any data source.

I've tried to analyze this sample from MSDN, it consists in some extension methods, but it takes a datatable and datasource, I don't have any dissapoint to use a datatable and datasource but just I don't know how to adapt the code-sample for my DataGridView. Anyways the sample does not support multi selection:

Move rows up/down and remember order for DataGridView and ListBoxs data bound

I also have seen some C# questions about this on StackOverflow but they asks for single row selection:

How to move gridview selected row up/down on KeyUp or Keydown press

DataGridView Selected Row Move UP and DOWN

Then, I don't have an starting point, just these methods to move a SINGLE row that also does not preserve the Order value, if someone could guide me to extend the functionality for my needs: Private Sub Button_MoveUp_Click(sender As Object, e As EventArgs) _ Handles Button_MoveUp.Click

    Me.MoveUpSelectedRows(Me.DataGridView_Files)

End Sub

Private Sub Button_MoveDown_Click(sender As Object, e As EventArgs) _
Handles Button_MoveDown.Click

    Me.MoveDownSelectedRows(Me.DataGridView_Files)

End Sub

Private Sub MoveUpSelectedRows(ByVal dgv As DataGridView)

    Dim curRowIndex As Integer = dgv.CurrentCell.RowIndex
    Dim newRowIndex As Integer = curRowIndex - 1

    Dim curColIndex As Integer = dgv.CurrentCell.ColumnIndex
    Dim curRow As DataGridViewRow = dgv.CurrentRow

    If (dgv.SelectedCells.Count > 0) AndAlso (newRowIndex >= 0) Then

        With dgv
            .Rows.Remove(curRow)
            .Rows.Insert(newRowIndex, curRow)
            .CurrentCell = dgv(curColIndex, newRowIndex)
        End With

    End If

End Sub

Private Sub MoveDownSelectedRows(ByVal dgv As DataGridView)

    Dim curRowIndex As Integer = dgv.CurrentCell.RowIndex
    Dim newRowIndex As Integer = curRowIndex + 1

    Dim curColIndex As Integer = dgv.CurrentCell.ColumnIndex
    Dim curRow As DataGridViewRow = dgv.CurrentRow

    If (dgv.SelectedCells.Count > 0) AndAlso (dgv.Rows.Count > newRowIndex) Then

        With dgv
            .Rows.Remove(curRow)
            .Rows.Insert(newRowIndex, curRow)
            .CurrentCell = dgv(curColIndex, newRowIndex)
        End With

    End If

End Sub

UPDATE

I'm trying @Plutonix approach (with a little modification), the only problem is that it does not move properly the selected rows to UP direction.

Steps to reprduce the issue:

Select two rows that are together (eg. row index 2 and row index 3, NOT row index 2 and row index 4)
Try to move the rows to UP direction.

How I could fix it?.

Public Enum MoveDirection As Integer
    Up = -1
    Down = 1
End Enum

Private Sub MoveRows(ByVal dgv As DataGridView, ByVal moveDirection As MoveDirection)

    Dim rows As DataGridViewRowCollection = dgv.Rows

    ' row index
    Dim thisRow As DataGridViewRow

    ' put selection back
    Dim selectedRows As New List(Of Integer)

    ' max rows
    Dim lastRowIndex As Integer =
        If(dgv.AllowUserToAddRows,
           rows.Count - 2,
           rows.Count - 1)



    For n As Integer = lastRowIndex To 0 Step -1

        If Not rows(n).IsNewRow Then

            If rows(n).Selected Then

                selectedRows.Add(n)

                MsgBox(n)

                Select Case moveDirection

                    Case Main.MoveDirection.Down
                        If ((n + moveDirection) <= lastRowIndex) AndAlso (n + moveDirection >= 0) AndAlso rows(n + moveDirection).Selected = False Then

                            selectedRows(selectedRows.Count - 1) = (n + moveDirection)
                            thisRow = rows(n)
                            rows.Remove(thisRow)

                            rows.Insert(n + moveDirection, thisRow)

                        End If

                    Case Main.MoveDirection.Up

                        If ((n + moveDirection) <= lastRowIndex) Then

                            MsgBox(selectedRows(selectedRows.Count - 1))
                            selectedRows(selectedRows.Count - 1) = (n + moveDirection)
                            thisRow = rows(n)
                            rows.Remove(thisRow)

                            rows.Insert(n + moveDirection, thisRow)

                        End If

                End Select

            End If

        End If

    Next n

    ' reselect the original selected rows
    For n As Integer = 0 To lastRowIndex

        dgv.Rows(n).Selected = selectedRows.Contains(n)

        ' renumber the order (optional & unknown, but trivial)
        dgv.Rows(n).Cells(0).Value = (n + 1)

    Next n

End Sub

what do you mean "the "Order" value should be inmutable"? When these 2 rows move down one, after are they (2, 4) or (3, 5)? Immutable would mean they do not change, which would mean the visible order would not match the number shown for the Order. That would seem to be confusing. — Ňɏssa Pøngjǣrdenlarp
Yes, visible index should not change, you understood perfect what I mean , don't worry :) and thanks. — ElektroStudios

Ňɏssa Pøngjǣrdenlarp Ňɏssa Pøngjǣrdenlarp · Accepted Answer · 2015-06-14T20:27:45

(Updated)
You need to iterate the rows collection, test if each is selected, then swap rows. In order to keep 2 selected rows from swapping with each other when they get to the top or bottom, a separate Up and Down method are needed.

' list of hash codes of the selected rows
Private Function GetSelectedRows() As List(Of Integer)
    Dim selR As New List(Of Integer)

    ' have to clear selected so the NEXT row 
    ' doesnt cause odd behavior
    For n As Integer = 0 To dgv.Rows.Count - 1
        If dgv.Rows(n).IsNewRow = False AndAlso dgv.Rows(n).Selected Then
            selR.Add(dgv.Rows(n).GetHashCode)
            dgv.Rows(n).Selected = False
        End If
    Next
    Return selR
End Function

' restore original selected rows
Private Sub SetSelectedRows(selRows As List(Of Integer))

    For n As Integer = 0 To dgv.Rows.Count - 1
        If dgv.Rows(n).IsNewRow = False Then
            dgv.Rows(n).Selected = selRows.Contains(dgv.Rows(n).GetHashCode)
            ' reset Order col:
            dgv.Rows(n).Cells(0).Value = n + 1
        End If
    Next
End Sub

Private Sub MoveRowsUp()
    ' short ref
    Dim rows As DataGridViewRowCollection = dgv.Rows
    ' row index
    Dim thisRow As DataGridViewRow
    ' put selection back
    Dim selectedRows As List(Of Integer)
    ' max rows
    Dim LastRow = If(dgv.AllowUserToAddRows, rows.Count - 2, rows.Count - 1)

    selectedRows = GetSelectedRows()

    For n As Int32 = 0 To LastRow
        If rows(n).IsNewRow = False Then

            If (selectedRows.Contains(rows(n).GetHashCode)) AndAlso (n - 1 >= 0) AndAlso
                (selectedRows.Contains(rows(n - 1).GetHashCode) = False) Then

                thisRow = rows(n)
                rows.Remove(thisRow)
                rows.Insert(n - 1, thisRow)
            End If
        End If
    Next

    SetSelectedRows(selectedRows)

End Sub

Private Sub MoveRowsDn()
    Dim rows As DataGridViewRowCollection = dgv.Rows
    Dim thisRow As DataGridViewRow
    Dim selectedRows As New List(Of Integer)
    Dim LastRow = If(dgv.AllowUserToAddRows, rows.Count - 2, rows.Count - 1)

    selectedRows = GetSelectedRows()

    For n As Int32 = LastRow To 0 Step -1

        If rows(n).IsNewRow = False Then
            If (selectedRows.Contains(rows(n).GetHashCode)) AndAlso (n + 1 <= LastRow) AndAlso
                         (selectedRows.Contains(rows(n + 1).GetHashCode) = False) Then
                thisRow = rows(n)
                rows.Remove(thisRow)
                rows.Insert(n + 1, thisRow)
            End If
        End If
    Next

    SetSelectedRows(selectedRows)

End Sub

Usage:

 MoveRowsUp()
 ' move down:
 MoveRowsDn()

Moving the rows causes the dgv to reset the selections. The methods first go thru and get a list of the HashCodes of the selected rows, then at the end resets each Row.Selected property based on that.

The code changes the value of Cell(0) so the order and Order column match (which means the Order column value is mutable).

Moving checks to see both if this row is at the end OR if the row at the destination is also selected. This prevents rows from swapping places when they get to the top or bottom.

Before:
enter image description here

After:
enter image description here

Note that when "Zalgo" got to the bottom (meaning 3 and 5 were selected), the other one could still move down one, so it did while "Ziggy" stayed put. The ability of "Ziggy(3)" to move down or not is based on the next row/index (only) - the next row is not beyond the bottom AND not selected so it can still move down 1, while "Zalgo (5)" could not.

Move up or down little complex DataGridView rows with multi-selection

2 Answers