C# Return 文件无法下载 Excel 文件

Question

我正在尝试使用 MVC 项目下载这样的文件：

控制器：

  [HttpPost]
        [ActionName("ExportList")]
        public async Task<IActionResult> ExportList(List<object> objectList)
        {
            var fileName = "fileName" ".xlsx";
            try
            {
                var fileContent = await _serviceLayer.ExportListToExcel(objectList);
                return File(fileContent, "application/vnd.ms-excel", fileName);
                // return new JsonResult("ok");
            }
            catch(Exception ex)
            {
                return BadRequest(ex.Message);
            }
        }

然后我的服务层：

public Task<byte[]> ExportListToExcel(List<object> objectList)
        {
            try
            {
               using(var workbook = new XLWorkbook())
                {
                    var worksheet = workbook.Worksheets.Add("Report");
                    var currentRow = 1;

                    #region Header
                    worksheet.Cell(currentRow, 1).Value = "val1";
                    worksheet.Cell(currentRow, 2).Value = "val2";
                    worksheet.Cell(currentRow, 3).Value = "val3";
                    #endregion

                    #region Body
                    foreach(var obj in objectList)
                    {
                        currentRow++;
                        worksheet.Cell(currentRow, 1).Value = obj.val1;
                        worksheet.Cell(currentRow, 2).Value = obj.val2;
                        worksheet.Cell(currentRow, 3).Value = obj.val3;
                    }
                    #endregion

                    using(var stream = new MemoryStream())
                    {
                        workbook.SaveAs(stream);
                        var content = stream.ToArray();

                        return Task.FromResult(content);
                    }
                }
            }
            catch (Exception ex)
            {
                throw new Exception("Error");
            }
        }

我调用控制器方法 ajax:

 function exportList() {
                 $.ajax({
                    type: "POST",
                    url: "@Url.Action("ExportList")",
                     data: { objectList: objectList},
                    dataType: "json",
                    success: function (data) {
                       //show success message
                    }, error: function (req, status, error) {
                       //show error message
                  }
            });
        }

我读了很多帖子，这基本上是他们建议下载文件的内容，但我返回到视图时出现以下错误消息，文件没有被下载，但控制器没有抛出任何类型的异常消息：

有下载文件的想法吗？

Answer 1

试试 Blob responseType,

$.ajax({
   type: "POST",
   url: "@Url.Action("ExportList")",
   data: { objectList: objectList},
   xhrFields: {
      responseType: 'blob' // FileContentResult will return as blob
   },
   success: function (data) {
      const url = window.URL.createObjectURL(data); // create url from blob
      const link = document.createElement('a'); // create anchor at DOM
      link.href = url; 
      link.setAttribute('download', 'file.xlsx'); // download attribute
      document.body.appendChild(link);
      link.click(); // trigger click for download
   },
   error: function (req, status, error) {
      //show error message
   }
});

Answer 2

您好，您的问题是 javascript 函数 exportList() 最好在文件所在的位置创建重定向，然后下载它。在您的导出方法中

这将是您的 ExportList 控制器方法的一部分：

// Generate a new unique identifier against which the file can be stored
                string handle = Guid.NewGuid().ToString();    
                using (MemoryStream memoryStream = new MemoryStream())
                {
                   //save your file to memory stream
                    workbook.SaveAs(memoryStream);
                    memoryStream.Position = 0;
                    TempData[handle] = memoryStream.ToArray();
                }
    
                // Note we are returning a filename as well as the handle
                return new JsonResult()
                {
                    Data = new { FileGuid = handle, FileName = "exporfile.xlsx" , FileType="xlsx"}
                };

您的下载文件应如下所示：

 public virtual ActionResult Download(string fileGuid, string fileName, string fileType)
        {
            if (TempData[fileGuid] != null)
            {
                byte[] data = TempData[fileGuid] as byte[];
                if (fileType == "xlsx" || fileType == "xls")
                {
                    return File(data, "application/vnd.ms-excel", fileName);
                }
                else if (fileType == "pdf")
                {
                    return File(data, "application/pdf", fileName);
                }
                else
                {
                    //sin especificar...
                    return File(data, "application/octet-stream", fileName);
                }
            }
            else
            {
               
                return new EmptyResult();
            }
        }

然后更改您的导出列表方法：

 function exportList() {
                 $.ajax({
                    type: "POST",
                    url: "@Url.Action("ExportList")",
                     data: { objectList: objectList},
                    dataType: "json",
                    success: function (data) {
                       var response = JSON.parse(data);
                    window.location = '/YourController/Download?fileGuid=' + response.FileGuid + '&filename=' + response.FileName +'&fileType=' + response.FileType;
                    }, error: function (req, status, error) {
                       //show error message
                  }
        });
    }

C# Return 文件无法下载 Excel 文件

C# Return File not working to download an Excel file

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