System.IO problem Visual Studio 2008

Question

Hello I have a solution with a web app and multiple class libraries - this solution was created in Visual studio 2005 but was recently converted to a VS 2008 application. Since I've done this I can no longer perform any method or operation within the System.IO namespace - I get the following SecurityException: {Request for the permission of type 'System.Security.Permissions.FileIOPermission mscorlib Version=2.0.0.0 Culture=neutral PublicKeyToken=b77a5c561934e089' failed.} Now if I create a blank solution in 2005 (Which I still have installed) - I can use Directory.Create or File.Create just by adding Network service to the ACL for the folder I want to write to and it doesn't cause any problems at all. I have searched on the net for this and nothing has been useful or worked. I have tried creating a FileIOPermission type and asserting access to the folder but I don't really know how this works. How can I make System.IO's static methods and classes work again in Visual Studio 2008? Have I done/not done something that I needed to do when I installed 2008 and .NET framework 3/3.5? - Am I trying to use version 2.0 assemblies when I shouldn't be? Any help greatly appreciated.... Matt

John Penn · Answer

I was able to run the following MSDN sample code in both .NET 3.0 and 3.5 without any errors: using System; using System.IO; class Test { public static void Main() { string path = @c:	emp\MyTest.txt; if (!File.Exists(path)) { // Create a file to write to. using (StreamWriter sw = File.CreateText(path)) { sw.WriteLine(Hello); sw.WriteLine(And); sw.WriteLine(Welcome); } } // Open the file to read from. using (StreamReader sr = File.OpenText(path)) { string s = ; while ((s = sr.ReadLine()) != null) { Console.WriteLine(s); } } try { string path2 = path + temp; // Ensure that the target does not exist. File.Delete(path2); // Copy the file. File.Copy(path path2); Console.WriteLine({0} was copied to {1}. path path2); // Delete the newly created file. File.Delete(path2); Console.WriteLine({0} was successfully deleted. path2); } catch (Exception e) { Console.WriteLine(The process failed: {0} e.ToString()); } } } Is this code doing anything dramatically different from your code? Since you're trying to create directories from a web app I would look into the permissions of the directories amd files you're accessing... does the user account have the necessary access priveleges?

matt · Answer

I should add that this is an application running on a local machine not a shared server - there are no UNC paths or any other external resources.