从WebAPI ASPNetCore返回Excel文件

Question

我正在尝试创建WebAPI,它将使用ClosedXML库返回Excel文件.

如果我返回FileStreamResult,一切正常.但是,如果我将其更改为HttpResponseMessage,如此处讨论的Web API返回文件,我无法下载文件或查看内容并获取JSON字符串.

我想知道如何从这个HttpResponseMessage中提取文件内容.

我在浏览器或PostMan工具中测试过,我得到的是JSON字符串:

{
      "version": {
        "major": 1,
        "minor": 1,
        "build": -1,
        "revision": -1,
        "majorRevision": -1,
        "minorRevision": -1
      },
      "content": {
        "headers": [
          {
            "key": "Content-Disposition",
            "value": [
              "attachment; filename=ERSheet.xlsx"
            ]
          },
          {
            "key": "Content-Type",
            "value": [
              "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
            ]
          }
        ]
      },
      "statusCode": 200,
      "reasonPhrase": "OK",
      "headers": [],
      "requestMessage": null,
      "isSuccessStatusCode": true
    }

我的守则如下:

[HttpGet("ERSheet2")]
        public HttpResponseMessage ER_GenerateWBLWorksheet2()
        {
            MemoryStream stream = new MemoryStream();
            var workbook = new XLWorkbook();

            var SheetNames = new List<string>() { "15-16", "16-17", "17-18", "18-19", "19-20" };

            foreach (var sheetname in SheetNames)
            {
                var worksheet = workbook.Worksheets.Add(sheetname);

                worksheet.Cell("A1").Value = sheetname;
            }

            workbook.SaveAs(stream);
            stream.Seek(0, SeekOrigin.Begin);

            HttpResponseMessage result = new HttpResponseMessage(HttpStatusCode.OK);
            result.Content = new ByteArrayContent(stream.ToArray());
            result.Content.Headers.ContentDisposition = new System.Net.Http.Headers.ContentDispositionHeaderValue("attachment");
            result.Content.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
            result.Content.Headers.ContentDisposition.FileName = "ERSheet.xlsx";
            return result;
        }

更新

这个与使用ClosedXML的这个问题下载文件不同,因为我提到我已经通过使用'FileStreamResult'使其工作了.我问这个是因为这个评论"最好用它内部的StreamContent返回HttpResponseMessage." 在此线程中创建Web API返回文件.因此,尝试在.Net Core中使用HttpResponseMessage,并且不知道它不再支持Darin的答案.

Answer 1

在.NET Core上运行的ASP.NET Web API不再支持HttpResponseMessage.所以基本上它会尝试序列化你要返回JSON的这个对象的实例(好像它是你的简单视图模型).有一些compatibility shim hacks你可以使用,但一般来说,我会建议你使用更惯用的方法 - IActionResult从你的行动中返回一个实例:

[HttpGet("ERSheet2")]
public IActionResult ER_GenerateWBLWorksheet2()
{
    using (MemoryStream stream = new MemoryStream())
    {
        var workbook = new XLWorkbook();

        var SheetNames = new List<string>() { "15-16", "16-17", "17-18", "18-19", "19-20" };

        foreach (var sheetname in SheetNames)
        {
            var worksheet = workbook.Worksheets.Add(sheetname);

            worksheet.Cell("A1").Value = sheetname;
        }

        workbook.SaveAs(stream);
        stream.Seek(0, SeekOrigin.Begin);

        return this.File(
            fileContents: stream.ToArray(), 
            contentType: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", 

            // By setting a file download name the framework will
            // automatically add the attachment Content-Disposition header
            fileDownloadName: "ERSheet.xlsx"
        );
    }
}