Download Excel File in .net core web api - asp.net-mvc

Question

I'm trying to create & download the excel file in asp .net core web api. Whenever I hit the service from postman or Advanced Rest Client, Instead of downloading the file I'm getting the JSON data of the file content as response. My code is like below :
[HttpGet]
[Route("GetLogsPdfORExcel")]
public IActionResult GetLogsPdfORExcel()
{
var result = _dataContext.GetLogsPdfORExcel();
if (result != null)
{
this.ExportExcel(result);
}
return Ok(result);
}
public FileStreamResult ExportExcel(DataTable dt)
{
string excelName = "LogsRecord";
ExcelPackage package = new ExcelPackage();
ExcelWorksheet worksheet = package.Workbook.Worksheets.Add("sheet1");
int currentRowNo = 5;
int totalRows = dt.Rows.Count;
int k = 0;
foreach (DataColumn column in dt.Columns)
{
worksheet.Cells[currentRowNo, k + 1].Value = column.ColumnName;
k++;
}
currentRowNo++;
for (int i = 0; i < dt.Rows.Count; i++)
{
for (int j = 0; j < dt.Columns.Count; j++)
{
worksheet.Cells[currentRowNo, j + 1].Value = Convert.ToString(dt.Rows[i][j]);
}
currentRowNo++;
}
int columnCount = dt.Columns.Count;
for (int i = 1; i <= columnCount; i++)
worksheet.Column(i).AutoFit();
worksheet.Row(1).Height = 55;
worksheet.SelectedRange["A1"].Style.Font.Size = 14;
worksheet.Row(5).Style.Font.Bold = true;
using (var memoryStream = new MemoryStream())
{
memoryStream.Position = 0;
var contentType = "application/octet-stream";
var fileName = "fileName.xlsx";
return File(memoryStream, contentType, fileName);
}
}
Here whenever I hit my service, I need directly my file needs to get download.

Answer 1

Return the file stream result and not the datatable.
[HttpGet]
[Route("GetLogsPdfORExcel")]
public IActionResult GetLogsPdfORExcel() {
var result = _dataContext.GetLogsPdfORExcel();
if (result != null) {
return this.ExportExcel(result);
}
return BadRequest(); //Or some other relevant response.
}
Also no need to dispose of the stream since the FileStreamResult will dispose of it when done
//...
var memoryStream = new MemoryStream();
using (var package = new ExcelPackage(memoryStream)) { //<<< pass stream
//...populate package
package.Save();
}
memoryStream.Position = 0;
var contentType = "application/octet-stream";
var fileName = "fileName.xlsx";
return File(memoryStream, contentType, fileName);