ClosedXML return File

Question

I'm using blazor and .net 5. I'm trying to do an excel export using ClosedXML. Here is the simple method I wrote:

public IActionResult CreateExcelSheet()
        {

            using (var wbook = new XLWorkbook())
            {
                var ws = wbook.Worksheets.Add("Sheet1");
                ws.Cell("A1").Value = "1";

                using (var stream = new MemoryStream())
                {
                    wbook.SaveAs(stream);
                    var content = stream.ToArray();
                    return File(content, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", "Opportunities.xlsx");
                }
            }
        }

The return file has a red underline saying Non-invocable member 'File' cannot be used like a method. I'm not really sure how to correct this... I'm also not sure if I'm doing this right with blazor and .net 5. Any help is greatly appreciated!

It probably thinks you are using System.IO.File. Try fully qualifying it — Crowcoder, Jun 18 '21 at 18:01
Your IActionResult needs to return a [ControllerBase.File](https://learn.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.mvc.controllerbase.file?view=aspnetcore-5.0) object or equivalent. Look here: https://stackoverflow.com/a/40488246/421195 or here: https://learn.microsoft.com/en-us/aspnet/core/blazor/file-uploads?view=aspnetcore-5.0&pivots=webassembly — paulsm4, Jun 18 '21 at 18:06

score 0 · Answer 1 · answered Jun 18 '21 at 18:26

I tried this and it works for me. Your URI is GET https:/api/sample/excel.

Sample: https://localhost:44370/api/Sample/excel

using System;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Http;
using ClosedXML.Excel;

namespace YourProject.API.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class SampleController : ControllerBase
    {
        [HttpGet("excel")]
        [AllowAnonymous]
        public IActionResult CreateExcelSheet()
        {
            try
            {
                using (var wbook = new XLWorkbook())
                {
                    var ws = wbook.Worksheets.Add("Sheet1");
                    ws.Cell("A1").Value = "1";

                    using (var stream = new System.IO.MemoryStream())
                    {
                        wbook.SaveAs(stream);
                        var content = stream.ToArray();
                        return File(content, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", "Opportunities.xlsx");
                    }
                }
            }
            catch (Exception ex)
            {
                return StatusCode(StatusCodes.Status500InternalServerError);
            }
        }
    }
}

I suspect one reason it's working for you - and not for the OP - is that you've got `using Microsoft.AspNetCore.Mvc` - which has `FileResult` - and the OP doesn't. As Crowcoder said: "t probably thinks you are using System.IO.File. Try fully qualifying it." — paulsm4, Jun 20 '21 at 23:32
Thanks Rodel! I was missing the ControllerBase. I was using CommonBase. So I created a new controller just for the excel methods and it works now! Thanks for your help! — EkHolland, Jun 21 '21 at 12:49

ClosedXML return File

1 Answers1