ASP.NET MVC - error while trying to read and write to text file

Question

currently I am trying to create two controller methods reading from file and writing to same file:

public ActionResult UploadText(string name)
{
    var path = Path.Combine(Server.MapPath("~/text/"), name);

    var fileContents = System.IO.File.ReadAllText(path);
    ViewData["text"] = fileContents;
    ViewData["textName"] = name;

    return View();
}

[HttpPost]
public ActionResult TextPost(string textName)
{
    string text = Request["text-content"];
    var path = Path.Combine(Server.MapPath("~/text/"), textName);

    System.IO.File.WriteAllText(path, text);

    return RedirectToAction("Index");
}

Reading file content and writing to it works, but it cannot be read second time, File can't be accessed because it is being used by another process error appears.

What am I doing wrong?

This is not a deadlock and singletons are not solutions for deadlocks. — Zdeslav Vojkovic, Mar 01 '16 at 14:08
What should happen if two concurrent requests arrive to edit the same file? — Zdeslav Vojkovic, Mar 01 '16 at 14:10
@ProgrammingDude **[File.ReadAllText](https://msdn.microsoft.com/en-us/library/ms143368.aspx)** and **[File.WriteAllText](https://msdn.microsoft.com/en-us/library/ms143375(v=vs.110).aspx)** do not require to close the file explicitly. — Win, Mar 01 '16 at 14:20
If that's not the case, then I am not sure that the problem is with files being locked by your application. Any chance something else keeps them open? You can use tools like Handle.exe, ProcessExplorer, WhosLocking or similar? — Zdeslav Vojkovic, Mar 01 '16 at 14:36
I once had a similar issue until I realized that it is me locking the file by checking it in the text editor and forgetting about it :) — Zdeslav Vojkovic, Mar 01 '16 at 14:42

score 0 · Answer 1 · edited May 23 '17 at 10:28

0

System.IO.File.ReadAllText and System.IO.File.WriteAllText both close the file after they and finished with the file per the documentation. The issue stems from the async nature of the web and well if you have more than one request while the file is open you will get the error you are seeing. Here are some MSDN examples to get you started.

Here are a couple more links for your pleasure

edited May 23 '17 at 10:28

Community

1
1

answered Mar 01 '16 at 14:03

Craig Selbert

737
1
8
17

Unfortunately using 1st link's methods gives the same result – Marcin Zdunek Mar 01 '16 at 14:32

ASP.NET MVC - error while trying to read and write to text file

1 Answers1