C1TrueDBGrid Column footer error "Input string was not in correct format"

Question

//Code for textbox/insert

       dg.AllowAddNew = true;
       dg.MoveLast();
       this.dg.Row = this.dg.Row + 1;
       this.dg.Select();
       dg.Columns[0].Text = a;

       dg.Columns[1].Text = b;
       dg.UpdateData();

//Code for the footer

        int a = 0;
        double sum = 0;
        for (a = 0; a <= this.dg.Splits[0].Rows.Count - 1; a++)
        {
            sum += Convert.ToDouble(this.dg.Columns["AMOUNT"].CellValue(a));
        }
        this.dg.Columns["AMOUNT"].FooterText = sum.ToString("n");

//It works on other c1 grids, don't know why on this one doesn't

Answer 1

TrueDbGrid.Columns("Amount").FooterText = FormatNumber(0.0, 2, TriState.True, TriState.False, TriState.False).ToString