How to create and automatically download Excel file with c#.

Question

Hello,

I would like to create a sheet and then download it. I wrote the code, but unfortunately no download works.

var memoryStream = new MemoryStream();

using (ExcelPackage package = new ExcelPackage(memoryStream))
{
    ExcelWorksheet worksheet;
    worksheet = package.Workbook.Worksheets.Add(name);

    worksheet.Name = name;

    for (int i = 0; i < nameColumns.Length; i++)
    {
        worksheet.Cells[1, i + 1].Value = nameColumns[i];
    }

    package.Save();
}

memoryStream.Position = 0;
var contentType = "application/octet-stream";
var fileName = "fileName.xlsx";
return File(memoryStream, contentType, fileName);

Regards

Answer 1

Hi @1023 ,

What do you mean about the download not work, is there any error message?

Based on your code, it seems that you are using the EPPlus package to export data to excel, right? If that is the case, please check the EPPlus license.

I create an Asp.net 5 MVC application with the following code (use the Polyform Noncommercial license), everything works well on my side.

    public IActionResult DownloadExcelEPPlus()  
    {  
        // query data from database     
        var list = new List<UserInfo>()  
        {  
            new UserInfo { UserName = "catcher", Age = 18 },  
            new UserInfo { UserName = "james", Age = 20 },  
        };  
        var stream = new MemoryStream();  
        //required using OfficeOpenXml;  

        // If you use EPPlus in a noncommercial context  
        // according to the Polyform Noncommercial license:  
        ExcelPackage.LicenseContext = LicenseContext.NonCommercial;  
        using (var package = new ExcelPackage(stream))  
        {  
            var workSheet = package.Workbook.Worksheets.Add("Sheet1");  
            workSheet.Cells.LoadFromCollection(list, true);  
            package.Save();  
        }  
        stream.Position = 0;  
        string excelName = $"UserList-{DateTime.Now.ToString("yyyyMMddHHmmssfff")}.xlsx";  

        return File(stream, "application/octet-stream", excelName);    
        //return File(stream, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", excelName);  
    }  
    public IActionResult Privacy()  
    {  
        return View();  
    }  

Index.cshtml:

<a class="nav-link text-dark" asp-area="" asp-controller="Home" asp-action="DownloadExcelEPPlus">Download Excel Via EPPlus</a>  

The result as below:

Finally, if the above method still not working, you could try to use ClosedXML to export data to excel file.

You can refer the following steps and sample code:

In the Asp.net 5 MVC application, install the ClosedXML package via the Nuget.

Index.cshtml:

<a class="nav-link text-dark" asp-area="" asp-controller="Home" asp-action="DownloadExcel">Download Excel</a>  

Action method:

    //using closedxml  
    public IActionResult DownloadExcel()  
    {  
        List<Author> authors = new List<Author>  
        {  
            new Author { Id = 1, FirstName = "Joydip", LastName = "Kanjilal" },  
            new Author { Id = 2, FirstName = "Steve", LastName = "Smith" },  
            new Author { Id = 3, FirstName = "Anand", LastName = "Narayaswamy"}  
        };  

        //required using ClosedXML.Excel;  
        string contentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";  
        string fileName = "authors.xlsx";  
        try  
        {  
            using (var workbook = new XLWorkbook())  
            {  
                IXLWorksheet worksheet =  
                workbook.Worksheets.Add("Authors");  
                worksheet.Cell(1, 1).Value = "Id";  
                worksheet.Cell(1, 2).Value = "FirstName";  
                worksheet.Cell(1, 3).Value = "LastName";  
                for (int index = 1; index <= authors.Count; index++)  
                {  
                    worksheet.Cell(index + 1, 1).Value = authors[index - 1].Id;  
                    worksheet.Cell(index + 1, 2).Value = authors[index - 1].FirstName;  
                    worksheet.Cell(index + 1, 3).Value = authors[index - 1].LastName;  
                }  
                //required using System.IO;  
                using (var stream = new MemoryStream())  
                {  
                    workbook.SaveAs(stream);  
                    var content = stream.ToArray();  
                    return File(content, contentType, fileName);  
                }  
            }  
        }  
        catch (Exception ex)  
        {  
            return Error();  
        }  
    }  

The result as below:

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Best regards,
Dillion