Check if file exist on server to read and write

Question

I'm trying to use System.Web; to read and write into text document located on server from winform desktop application. First of all need to check if file exist. Not sure why, but System.Web does not works it is added for References as System.Web

string siteDir = "http://www.site.info/doc.txt";

if (File.Exists(Server.MapPath(siteDir)));

same with System.Web.HttpContext

System.Web.HttpContext.Current.Server.MapPath(siteDir);

Try `System.Web.Hosting.HostingEnvironment.MapPath(siteDir);` — Stanley S, Mar 14 '17 at 01:53
Is this a desktop application or a web application? You have put a winforms tag in there, which suggests this is a desktop app — Sparrow, Mar 14 '17 at 01:54
@StanleyS Hello. No, same result, I using System.Web; maybe I need some reference to use it? — nikorio, Mar 14 '17 at 02:00
@StanleyS yes it is done. It is System.Web there, not System.Web.dll but seems like it must be same. But same result, does not works — nikorio, Mar 14 '17 at 02:11
@nikorio So you see `System.Web` under References in the Solution Explorer ? — Stanley S, Mar 14 '17 at 02:13
Explain "does not work". Are you getting a compile error? An exception? Code runs but gives a different result? — Ben Voigt, Mar 14 '17 at 02:39

score 1 · Accepted Answer · edited May 23 '17 at 11:54

1

A simple way to do this is to use WebClient.DownloadFile() to attempt to download a file from a url like the one you are using. If a WebException is thrown and the HTTP Error is 404 File Not Found, then the file does not exist on the server (or you do not have access to it).

See: How to catch 404 WebException for WebClient.DownloadFileAsync for info on how to detect a 404 error.

Unfortunately there is no WebClient method that will simply check to see if a file is present on the server.

edited May 23 '17 at 11:54

Community

1
1

answered Mar 14 '17 at 03:07

Keith Payne

3,002
16
30

Hello, thanks, so I did it this way HttpWebResponse resp = ex.Response as HttpWebResponse; if (resp.StatusCode == HttpStatusCode.NotFound) { //404 } – nikorio Mar 14 '17 at 04:17

score -1 · Answer 2 · answered Mar 14 '17 at 02:31

-1

use System.IO.File.Exists() 

if(System.IO.File.Exists([path of file]))
{
  // do something
}

answered Mar 14 '17 at 02:31

AKN

416
2
5

Check if file exist on server to read and write

2 Answers2