c# - Checking if file exists in asp.net mvc 5

Question

I am checking for the existence of a file bu cannot find it, regardless of whether it is there or not

if (System.IO.File.Exists("~/files/downloads/" + fileCode + ".pdf"))
            {
                return File("~/files/downloads/" + fileCode, "application/pdf", Server.UrlEncode(fileCode));
            }
            else
            {
                return View("ErrorNotExistsView");
            }

How can I amend the code to check for the existence of the file correctly?

Answer 1

System.IO.File will work if you provide an absolute path or a relative path. A relative path will not be relative to the HTML root folder, but the current working directory. The current working directory will be a value like C:Program Files (x86)IIS Express.

The ~ character at the beginning of the file path is only interpreted as part of the current ASP.NET context, which the File methods know nothing about.

The method to help you here is HttpServerUtility.MapPath

If you are in a controller method, you can invoke this method on the object HttpContext.Server, otherwise (e.g. in a View) you can use HttpContext.Current.Server.

 var relativePath = "~/files/downloads/" + fileCode + ".pdf";
 var absolutePath = HttpContext.Server.MapPath(relativePath);
 if(System.IO.File.Exists(absolutePath)) ....