Question

I Have a datatable in .net. I need to flip the location of two of them. For example, a datatable that the select statement had an order by priority clause. The user wants to up the priority of a single row by selecting it and clicking increase priority, how do i move a row up (AKA flip two rows)

Thanks in advance

Answer 1

Use a DataView on this table, sorted by an “priority” column. When you want to increase priority, increase this column, and decrease it on the row above. The DataView will reflect the change on the UI.

Private _view As DataView

...

_view = New DataView(theTable, "", "priority", DataViewRowState.CurrentRows)
dataGridView1.DataSource = _view

...


' Increase priority of row at index i
If i > 0 Then
    Dim row = _view(i)
    Dim previousRow = _view(i - 1)
    row("priority") = row("priority") + 1
    previousRow("priority") = previousRow("priority") - 1
End


...


' Decrease priority of row at index i
If i < _view.Count - 1 Then
    Dim row = _view(i)
    Dim nextRow = _view(i + 1)
    row("priority") = row("priority") - 1
    nextRow ("priority") = nextRow ("priority") + 1
End

When you’re done changing the priorities, update the database using a DataAdapter