Microsoft.Office.Interop.Excel 添加单元格非常慢

public async Task<HttpResponseMessage> GetImage()
    {
         excelApp.Application app = new excelApp.Application();
        excelApp.Workbook wb = app.Workbooks.Add(excelApp.XlWBATemplate.xlWBATWorksheet);
        excelApp.Worksheet ws = (excelApp.Worksheet) wb.Worksheets.get_Item(1);
        for (int i = 0; i < 21000; i++)
        {
            for (int j = 0; j < 8; j++)
            {
                
                excelApp.Range aRange = ws.Cells[i + 2,j+1];
                
                aRange.Value2 = i + j;
            }
        }
       
        wb.SaveAs("d:''example2.xlsx");
        wb.Close();        }

我需要在不打开 excel 的情况下创建 xlsx 文件。那对于工作非常慢..我做错了什么？？