C# Downloadable Excel Files from Class Library

I'm looking for some advice. I'm building on an additional feature to a C# project that someone else wrote. The solution of the project consists of an MVC web application, with a few class libraries.

What I'm editing is the sales reporting function. In the original build, a summary of the sales reports were generated on the web application. When the user generates the sales report, a Reporting class is called in one of the C# class libraries. I'm trying to make the sales reports downloadable in an excel file when the user selects a radio button.

Here is a snippet of code from the Reporting class:

public AdminSalesReport GetCompleteAdminSalesReport(AdminSalesReportRequest reportRequest)
        {
            AdminSalesReport report = new AdminSalesReport();
            string dateRange = null;
            List<ProductSale> productSales = GetFilteredListOfAdminProductSales(reportRequest, out dateRange);

            report.DateRange = dateRange;

            if (titleSales.Count > 0)
            {
                report.HasData = true;

                report.Total = GetTotalAdminSales(productSales);

                if (reportRequest.Type == AdminSalesReportRequest.AdminSalesReportType.Complete)
                {
                    report.ProductSales = GetAdminProductSales(productSales);

                    report.CustomerSales = GetAdminCustomerSales(productSales);

                    report.ManufacturerSales = GetAdminManufacturerSales(productSales);

                    if (reportRequest.Download)
                    {
                        FileResult ExcelDownload = GetExcelDownload(productSales);
                    }

                }
            }

            return report;
        }

So as you can see, if reportRequest.Download == true, the class should start up the process of creating the excel file. All the GetAdminSales functions do it use linq queries to sort out the sales if they are being displayed on the webpage.

So I have added this along with the GetAdminSales functions:

private FileResult GetExcelDownload(List<TitleSale> titleSales)
{
    CustomisedSalesReport CustSalesRep = new CustomisedSalesReport();

    Stream SalesReport = CustSalesRep.GenerateCustomisedSalesStream(productSales);

    return new FileStreamResult(SalesReport, "application/ms-excel")
    {
        FileDownloadName = "SalesReport" + DateTime.Now.ToString("MMMM d, yyy") + ".xls"
    };
}

and to format the excel sheet, I'm using the NPOI library, and my formatter class is laid out like so:

public class CustomisedSalesReport
    {
        public Stream GenerateCustomisedSalesStream(List<ProductSale> productSales)
        {
            return GenerateCustomisedSalesFile(productSales);
        }

        private Stream GenerateCustomisedSalesFile(List<ProductSale> productSales)
        {
            MemoryStream ms = new MemoryStream();
           开发者_StackOverflow中文版 HSSFWorkbook templateWorkbook = new HSSFWorkbook();

            HSSFSheet sheet = templateWorkbook.CreateSheet("Sales Report");

            HSSFRow dataRow = sheet.CreateRow(0);
            HSSFCell cell = dataRow.CreateCell(0);

            cell = dataRow.CreateCell(0);
            cell.SetCellValue(DateTime.Now.ToString("MMMM yyyy") + " Sales Report");

            dataRow = sheet.CreateRow(2);

            string[] colHeaders = new string[] {
                "Product Code",
                "Product Name",
                "Qty Sold",
                "Earnings",
            };

            int colPosition = 0;

            foreach (string colHeader in colHeaders)
            {
                cell = dataRow.CreateCell(colPosition++);
                cell.SetCellValue(colHeader);
            }

            int row = 4;

            var adminTotalSales = GetAdminProductSales(productSales);


            foreach (SummaryAdminProductSale t in adminTotalSales)
            {
                dataRow = sheet.CreateRow(row++);
                colPosition = 0;

                cell = dataRow.CreateCell(colPosition++);
                cell.SetCellValue(t.ProductCode);

                cell = dataRow.CreateCell(colPosition++);
                cell.SetCellValue(t.ProductName);

                cell = dataRow.CreateCell(colPosition++);
                cell.SetCellValue(t.QtySold);

                cell = dataRow.CreateCell(colPosition++);
                cell.SetCellValue(t.Total.ToString("0.00"));
            }

            }
        templateWorkbook.Write(ms);
        ms.Position = 0;

            return ms;

        }

Again like before, the GetAdminSales (GetAdminProductSales, etc) are contained in the bottom of the class, and are just linq queries to gather the data.

So when I run this, I don't get any obvious errors. The summary sales report appears on screen as normal but no excel document downloads. What I have done, which may be putting this off is in my class library I have referened the System.Web.Mvc dll in order to download the file (I have not done it any other way before - and after reading up on the net I got the impression I could use it in a class library).

When I debug through the code to get a closer picture of what's going on, everything seems to be working ok, all the right data is being captured but I found that from the very start - the MemoryStream ms = new Memory Stream declaration line in my formatter class shows up this (very hidden mind you) :

ReadTimeout '((System.IO.Stream)(ms)).ReadTimeout' threw an exception of type 'System.InvalidOperationException' int {System.InvalidOperationException}

+{"Timeouts are not supported on this stream."} System.SystemException {System.InvalidOperationException}

I get the same for 'WriteTimeout'...

Apologies for the long windedness of the explaination. I'd appreciate it if anyone could point me in the right direction, either to solve my current issue, or an alternative way of making this work.

Without getting bogged down in the details, the obvious error is that in GenerateCustomisedSalesFile you create a MemoryStream ms, do nothing with it, then return it.