I found this VB code here and was pulling my hair out until i realized one thing...
I had not changed the Design Name of the columns so they were still that default names like DataGridViewTextBoxColumn1 , DataGridViewTextBoxColumn2 , DataGridViewTextBoxColumn6 , etc
DOH!
So in case this happens to you, be sure to check that the Design Name in the Bound Column Properties in the Edit Columns dialog that pops up when you choose to edit columns of a DataGridView is something other than the default name.
Private Sub DataGridView1_CellEndEdit(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.CellEndEdit
' If the column is the Quantity column, compute the line total.
If Me.DataGridView1.Columns(e.ColumnIndex).Name = "QuantityColumn" Or Me.DataGridView1.Columns(e.ColumnIndex).Name = "SalePriceColumn" Then
Dim dblSalePrice As Double
Dim dblQuantity As Double
Dim dblLineTotal As Double
dblSalePrice = CDbl(Me.DataGridView1.CurrentRow.Cells("SalePriceColumn").Value)
dblQuantity = CDbl(Me.DataGridView1.CurrentRow.Cells("QuantityColumn").Value)
dblLineTotal = dblSalePrice * dblQuantity
Me.DataGridView1.CurrentRow.Cells("LineTotalColumn").Value = dblLineTotal
End If
End Sub
