Moving rows up and down in a datagridview and updating the database - vb.net

Question

I have a datagridview and I am getting all the data from a sql database I want to be able to move rows from one position to the other either up or down and it should also reflect the same in the database.
Currently this is what I have done and it does move the items as desired ( am adding 100 to the value of the column that am using to move up and subtracting 100 when moving down) but the problem with this is that if it find that the value of the next item in the row is lower, it doesnt move or if you add 100 then its value suddenly becomes more that 3 items above it, it doesnt move to the next position instead it moves 3 positions up, how can I simplify it to make it move just 1 row above or below respectively.
Private Sub BntMoveUp_Click(sender As Object, e As EventArgs) Handles BntMoveUp.Click
For i As Integer = 0 To DataGridView2.Rows.Count() - 1
Dim c As Boolean
c = DataGridView2.Rows(i).Cells(0).Value
' if the checkbox cell is checked
If c = True Then
' MessageBox.Show("Checked")
Dim cid As Integer = DataGridView2.Rows(i).Cells(1).Value
Dim cid2 As Integer = DataGridView2.Rows(i - 1).Cells(1).Value
Str = "update Production..CMBGSeat_Staging set [Priority] =[Priority] > 1 where cid=" & cid
updaterecords(Str)
Dim cmd As Odbc.OdbcCommand
Dim LDataadapter As Odbc.OdbcDataAdapter
Dim MyDataset As DataSet
Dim insert As String
con()
insert = "select * from Production..CMBGSeat_Staging where DateCompleted is null order by Priority desc"
cmd = New Odbc.OdbcCommand(insert, sqlcon)
LDataadapter = New Odbc.OdbcDataAdapter
LDataadapter.SelectCommand = cmd
MyDataset = New DataSet
' MyDataset = New DataSet
LDataadapter.Fill(MyDataset)
DataGridView2.DataSource = MyDataset.Tables(0)
' if not
Else
' MessageBox.Show("Not Checked")
End If
Next
End Sub
Private Sub BtnMoveDown_Click(sender As Object, e As EventArgs) Handles BtnMoveDown.Click
For i As Integer = 0 To DataGridView2.Rows.Count() - 1
Dim c As Boolean
c = DataGridView2.Rows(i).Cells(0).Value
'If the Then checkbox cell Is checked
If c = True Then
' MessageBox.Show("Checked")
Dim cid As Integer = DataGridView2.Rows(i).Cells(1).Value
Dim cid2 As Integer = DataGridView2.Rows(i + 1).Cells(1).Value
Str = "update Production..CMBGSeat_Staging set [Priority] =[Priority] < 1 where cid=" & cid
updaterecords(Str)
Dim cmd As Odbc.OdbcCommand
Dim LDataadapter As Odbc.OdbcDataAdapter
Dim MyDataset As DataSet
Dim insert As String
con()
insert = "select * from Production..CMBGSeat_Staging where DateCompleted is null order by Priority desc"
cmd = New Odbc.OdbcCommand(insert, sqlcon)
LDataadapter = New Odbc.OdbcDataAdapter
LDataadapter.SelectCommand = cmd
MyDataset = New DataSet
MyDataset = New DataSet
LDataadapter.Fill(MyDataset)
DataGridView2.DataSource = MyDataset.Tables(0)
' if not
Else
'MessageBox.Show("Not Checked")
End If
Next
End Sub