process cannot access the file because it is being

问题:

I am using ASP.NET Webforms with C#. On one page I click submit to create a file on the server.

File.Create(Server.MapPath(ConfigurationManager.AppSettings["LandingPages"])
            + landingPage.FriendlyName);

This works fine and creates the file as expected. However, after it does this it redirects to another page, which reads the file that was just created.

var landingPageContent 
       = File.ReadAllText(Server.MapPath(ConfigurationManager.AppSettings["LandingPages"]) 
                          + landingPage.FriendlyName);

That's when I get this error.

The process cannot access the file 'c:\code\Content\CMS\LandingPages\Test2' because it is being used by another process.

If I restart IIS then the process releases the file and I can load that page and read the file just fine. Is there something I need to do after File.Create in order to close the file before the redirect?

回答1:

Did you close the stream returned by File.Create? The name is a bit confusing (it comes all the way from the bowels of WinAPI), but it creates a file and opens it for writing for you.

回答2:

File.Create returns Filstream, try this:

using (FileStream fs = System.IO.File.Create(...)){}

or shorter:

File.Create(...).Dispose();

回答3:

try replacing:

File.Create(Server.MapPath(ConfigurationManager.AppSettings["LandingPages"]) + landingPage.FriendlyName);

with:

using(File.Create(Server.MapPath(ConfigurationManager.AppSettings["LandingPages"]) + landingPage.FriendlyName))
{}

so the file handle is immedately disposed/released

回答4:

Just close it:

var fileStream = File.Create(...);
fileStream.Close();

If you are doing something with created file it would be better wrapping this logic by using block which finally would close a handle:

using (var stream = File.Create(...))
{
   // logic
}