Excel 下载后无法读取数据

Question

我正在尝试下载我提供了正确路径的 excel 文件。但是在我尝试打开时下载它后出现错误

excel cannot open the file because the file format or file extension is not valid. Verify that file has been corrupted...

在这一部分 class 我创建了导出函数来创建数据并将其写入 excel 文件

        public static ExcelPackage ExportExcel(string fileName, decimal projectId, ModelContext context)
    {
        ExcelPackage pck = new ExcelPackage();
        ExcelWorksheet ws = pck.Workbook.Worksheets.Add("Project");
        

        var surveys = context.Survey.Where(x => x.ProjectId == projectId)
            .Include(s=> s.Question);
        


        #region datatable

        

        

        ws.Cells["A1"].Value = "SURVEY_ID";
        ws.Cells["B1"].Value = "PAGE";
        ws.Cells["C1"].Value = "RANKING";
        ws.Cells["D1"].Value = "PARENT_ID";
        ws.Cells["E1"].Value = "ID";
        ws.Cells["F1"].Value = "ITEMTYPE";
        ws.Cells["G1"].Value = "CONTROLTYPE";
        ws.Cells["H1"].Value = "DISPLAYTYPE";
        ws.Cells["J1"].Value = "VARIABLE_DESCRIPTION";
        ws.Cells["K1"].Value = "VARIABLE_NAME";
        ws.Cells["L1"].Value = "VARIABLE_LABEL";
        ws.Cells["M1"].Value = "VALUE_LABEL_ID";
        ws.Cells["N1"].Value = "MISSING_VALUE_ID";
        ws.Cells["O1"].Value = "IS_REQUIRED";
        ws.Cells["P1"].Value = "DATA_TYPE";
        ws.Cells["Q1"].Value = "VARIABLE_LENGTH";
        ws.Cells["R1"].Value = "NR_OF_DECIMALS";
        ws.Cells["S1"].Value = "COMMENT";
        ws.Cells["T1"].Value = "COMMENT_TYPE";
        ws.Cells["U1"].Value = "SHOW_ALL_FOR_STUDY";
        ws.Cells["V1"].Value = "ANSWER_FONT";
        ws.Cells["W1"].Value = "IS_DELETE_QUESTION";
        ws.Cells["X1"].Value = "IS_STOP_QUESTION";
        ws.Cells["Y1"].Value = "ROUTING_TYPE";
        ws.Cells["Z1"].Value = "ROUTING_VALUE";
        ws.Cells["AA1"].Value = "SHOW";

        int rowStart = 2;
        foreach (var survey in surveys)
        {

            foreach (var item in survey.Question)
            {
                ws.Cells[String.Format("A{0}", rowStart)].Value = survey.IdSurvey;
                ws.Cells[String.Format("B{0}", rowStart)].Value = item.Page;
                ws.Cells[String.Format("C{0}", rowStart)].Value = item.Ranking;
                ws.Cells[String.Format("D{0}", rowStart)].Value = item.ParentId;
                ws.Cells[String.Format("E{0}", rowStart)].Value = item.IdQuestion;
                ws.Cells[String.Format("F{0}", rowStart)].Value = item.Itemtype;
                ws.Cells[String.Format("G{0}", rowStart)].Value = item.Controltype;
                ws.Cells[String.Format("H{0}", rowStart)].Value = item.Displaytype;
                ws.Cells[String.Format("J{0}", rowStart)].Value = item.VariableDescription;
                ws.Cells[String.Format("K{0}", rowStart)].Value = item.VariableName;
                ws.Cells[String.Format("L{0}", rowStart)].Value = item.VariableLabel;
                ws.Cells[String.Format("M{0}", rowStart)].Value = item.ValueLabelId;
                ws.Cells[String.Format("N{0}", rowStart)].Value = item.MissingValueId;
                ws.Cells[String.Format("O{0}", rowStart)].Value = item.IsRequired;
                ws.Cells[String.Format("P{0}", rowStart)].Value = item.DataType;
                ws.Cells[String.Format("Q{0}", rowStart)].Value = item.VariableLength;
                ws.Cells[String.Format("R{0}", rowStart)].Value = item.NrOfDecimals;
                ws.Cells[String.Format("S{0}", rowStart)].Value = item.Comment;
                ws.Cells[String.Format("T{0}", rowStart)].Value = item.CommentType;
                ws.Cells[String.Format("U{0}", rowStart)].Value = item.ShowAllForStudy;
                ws.Cells[String.Format("V{0}", rowStart)].Value = item.AnswerFont;
                ws.Cells[String.Format("W{0}", rowStart)].Value = item.IsDeleteQuestion;
                ws.Cells[String.Format("X{0}", rowStart)].Value = item.IsStopQuestion;
                ws.Cells[String.Format("Y{0}", rowStart)].Value = item.RoutingType;
                ws.Cells[String.Format("Z{0}", rowStart)].Value = item.RoutingValue;
                ws.Cells[String.Format("AA{0}", rowStart)].Value = item.Show;
                rowStart++;
            }
            
            ws.Cells["A:AZ"].AutoFitColumns();
            


        }
        #endregion

        return pck;

    }
}

然后我从控制器调用这个函数：

      [HttpGet("{Id}")]
    public IActionResult Export(IFormCollection form, decimal? id)
    {

        var exportId = _context.Project.First(x => x.ProjectId == id).ProjectId;
        var fileName = form["Codebook.xlsx"];

        //var pck = Models.Export.ExportExcel(fileName, exportId, _context);
        return File(Models.Export.ExportExcel(fileName, exportId, _context).Stream
            , "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", "Codebook.xlsx");

Answer 1

我不知道这是否重要：我们使用与您相同的内容类型，但我们将 ContentEncoding 设置为 System.Text.Encoding.UTF8。简化代码：

public System.Web.Mvc.ActionResult Export(string filename)
{
            Response.AppendHeader("Content-Disposition", string.Format("attachment; filename*=UTF-8''{0}", Uri.EscapeDataString(filename)));
            Response.ContentEncoding = System.Text.Encoding.UTF8;
            Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
            Stream ms = <<Excel file content>>
            return new FileStreamResult(ms, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
}

Answer 2

文件应首先保存在 webroot 中，然后 return 将其保存为字节数组所以在控制器中添加 IwebHostEnviroment 然后更新操作方法

        public IActionResult Export(IFormCollection form, decimal? id)
    {
        var project = _context.Project.First(x => x.ProjectId == id).ProjectId;
        var fileName = form["Codeboek"];
        var pck = Models.Export.ExportExcel(fileName, project, _context);

        var contentRootPath = _env.ContentRootPath;
        fileName = "exportFile.xlsx";
        
        
        var filePath = contentRootPath + "/" + fileName;
        pck.SaveAs(new FileInfo(filePath));
        byte[] fileBytes = System.IO.File.ReadAllBytes(filePath);

        return File(fileBytes, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", fileName);
    }

Excel 下载后无法读取数据

Excel cannot read the data after i download it

c#

model-view-controller

excel

asp.net-core