检查 excel 第 3 列中的每个值，如果小于 4，则更改行颜色?C#.

我正在创建一个Excel工作表并使用c#填充值。

在保存之前，我想检查 excel 工作表的第 3 列并检查每个值是否小于 4。如果是，我想将该行更改为红色。

这是我到目前为止尝试过的：

            Microsoft.Office.Interop.Excel.Application excel;
            Microsoft.Office.Interop.Excel.Workbook worKbooK;
            Microsoft.Office.Interop.Excel.Worksheet worKsheeT;
            Microsoft.Office.Interop.Excel.Range celLrangE;
            int totalcount = 0;

            excel = new Microsoft.Office.Interop.Excel.Application();
            excel.Visible = false;
            excel.DisplayAlerts = false;
            worKbooK = excel.Workbooks.Add(Type.Missing);
            worKsheeT = (Microsoft.Office.Interop.Excel.Worksheet)worKbooK.ActiveSheet; worKsheeT.Name = "Model Results";

            worKsheeT.Cells[1, 1] = "Name";
            worKsheeT.Cells[1, 2] = "Id";
            worKsheeT.Cells[1, 3] = "Sales";

            for (int totalcount= 3; totalcount< dataGridView2.Columns.Count; )
            {
                GetSalesNumbers();
                worKsheeT.Cells[totalcount, 1] = Name;
                worKsheeT.Cells[totalcount, 2] =  Id;
                worKsheeT.Cells[totalcount, 3] = SalesNumber;
         totalcount ++;
            }

            celLrangE = worKsheeT.Range[worKsheeT.Cells[1, 1], worKsheeT.Cells[totalcount + 5, 15]];
            celLrangE.EntireColumn.AutoFit();

            Excel.Range usedRange = worKsheeT.UsedRange;
            Excel.Range rows = usedRange.Rows;
            int count = 0;
            foreach (Excel.Range row in rows)
            {
                if (count > 0)
                {
                    Excel.Range firstCell = row.Cells[count,3];
                    string firstCellValue = firstCell.Value as String;
                    if (Convert.ToDouble(firstCellValue)<4)
                    {
                        row.Interior.Color = System.Drawing.Color.Red;
                    }
                }
                count++;
            }

但这不起作用，它一直将单元格值获取为 Null

            celLrangE = worKsheeT.Range[worKsheeT.Cells[1, 1],worKsheeT.Cells[totalcount + 5, 15]];
            celLrangE.EntireColumn.AutoFit();


            for (int row = 3; row <= totalcount; row++)
            {
                if (Convert.ToDouble(worKsheeT.Cells[row, 3].Value) < 4)
                {
                    Excel.Range rows = worKsheeT.Range[worKsheeT.Cells[row,1],worKsheeT.Cells[row,15]];
                    rows.Interior.Color = System.Drawing.Color.Red;
                }

            }