在 asp.net 核心 2.2 上上传文件 API 时不能使用替换 function

Question

I work on ASP.NET Core 2.2 Web API and face an issue: I can't use replace function to change the name property of a selected file that I get when uploaded.

When I try like this:

string fileName = DisplayFileName.Replace(".xlsx", "-") + Guid.NewGuid().ToString() + ".xlsx";

I get an error

Iform file doesn't contain definition for replace and no accessible extension method Replace accepting first argument of iformfile

Full sample is here:

[HttpPost, DisableRequestSizeLimit]
public IActionResult Upload()
{
        try
        {
            var DisplayFileName = Request.Form.Files[0];
            string fileName = DisplayFileName.Replace(".xlsx", "-") + Guid.NewGuid().ToString() + ".xlsx";
            string Month = DateTime.Now.Month.ToString();
            string DirectoryCreate = myValue1 + Month;

            Path.Combine(Directory.GetCurrentDirectory(), folderName);

            if (!Directory.Exists(DirectoryCreate))
            {
                Directory.CreateDirectory(DirectoryCreate);
            }

            if (DisplayFileName.Length > 0)
            {
                var filedata = ContentDispositionHeaderValue.Parse(Request.Form.Files[0].ContentDisposition).FileName.Trim('"');
                var dbPath = Path.Combine(DirectoryCreate, fileName);
              
                using (var stream = new FileStream(dbPath, FileMode.Create))
                {
                    Request.Form.Files[0].CopyTo(stream);
                }

                return Ok(new { dbPath });
            }
            else
            {
                return BadRequest();
            }
        }
        catch (Exception ex)
        {
            return StatusCode(500, $"Internal server error: {ex}");
        }
}

How to solve this issue? sample

suppose i select file developed.xlsx

then after use replace or any way result will be

developed-sddfn78888.xlsx

Answer 1

You can use System.IO.Path to get filename and get file extension from request files. Change this string fileName = DisplayFileName.Replace(".xlsx", "-") + Guid.NewGuid().ToString() + ".xlsx"; To

string filename = Path.GetFileName(DisplayFileName.FileName);
string fileExtension = Path.GetExtension(DisplayFileName.FileName);
string newFileName = $"{filename}-{Guid.NewGuid().ToString()}{fileExtension}";

Otherwise, you could modify your code to

 string fileName = DisplayFileName.FileName.Replace(".xlsx", "-") + Guid.NewGuid().ToString() + ".xlsx";