Question

I want to write a .xml file using the following code into the App_Data/posts. Why is it causing an error?

Code

 Stream writer  = new FileStream("..'\'App_Data'\'posts'\'" + new Guid(post_ID.ToString()).ToString() + ".xml", FileMode.Create);

Answer 1

Please post the exception you are getting; not just “it does not work” – this can be all sorts of problems. Here is a few things to check:

Check whether the ASP.NET process has write access to that directory.

Also, it looks like you are escaping the backspaces in the path wrong. And when working with ASP.NET, your paths should be relative to the application root directory. Try this:

string path = HttpContext.Current.Server.MapPath("~/App_Data/posts/" + new Guid(post_ID.ToString()).ToString() + ".xml"
Stream writer  = new FileStream(path, FileMode.Create);

Finally, ensure that the posts directory exists – or the file creation will fail.