CODEWITHSUNDEEP
c#uwpvisual-studio-2017windows-10unauthorizedaccessexcepti
Tobias Nöthlich
Tobias Nöthlich

Reputation: 191

Unauthorized access exception while running as admin

I know that there are a lot of questions concerning getting a

"System.UnauthorizedAccessException".

However I couldn't find a solution in any of these questions, as most of the answers refer to one of these Microsoft help pages.

My Situation: I try to save some user input as .csv, so I can import it when needed.

My Code:

var csv = new System.Text.StringBuilder();
            string dir = Path.Combine(Environment.GetFolderPath
            (Environment.SpecialFolder.DesktopDirectory), "test.csv");

            var newLine = string.Format("{0},{1},{2},{3},{4}", txtFirstName.Text, txtLastName.Text, txtEmail.Text,
                txtPhone.Text, txtPlace.Text);

            csv.AppendLine(newLine);

            if (!File.Exists(dir))
            {

                using (FileStream fs = File.Create(dir))
                {
                    Byte[] info = new System.Text.UTF8Encoding(true).GetBytes("FirstName,LastName,Email,Phone,Place");
                    // Add headers to the file.
                    fs.Write(info, 0, info.Length);
                }
            }

            try
            {
                File.AppendAllText(dir, csv.ToString());
            }
            catch (Exception ex)
            {
                throw ex;
            }

As you can see, I'm trying to write everything to my Desktop, in a file called "test.csv". I am running Visual Studio as an Administrator and the file I have on my Desktop is not read-only. Does anybodoy have an idea why this still fails?

Edit: I'm running this as a Standard UWP-App on a desktop Computer.

Upvotes: 2

Views: 1589

Answers (1)

Stefan Wick MSFT
Stefan Wick MSFT

Reputation: 13850

From a UWP process file access is restricted. In order to write to the desktop (or any arbitrary location) your app will need to use the file save dialog and let the user confirm/choose the location. Then you will be able to save to the desktop or whatever location the user has decided to select.

In the upcoming Spring 2018 update for Windows 10 we will introduce a new capability ('broadFileSystemAccess') for UWP applications that will make this better. If you declare this capability in your manifest, the app will ask for user consent on first launch for broad file system access, and then you will be able to access all locations that the current user has access to.

If you need a solution that works on earlier versions of Windows 10 (prior to Spring 2018 update) and the file dialog is not a viable option then you can look into adding a fulltrust process to your UWP package that handles the file operations on behalf of your UWP process. You can launch that fulltrust process from the UWP via the FullTrustProcessLauncher API: https://learn.microsoft.com/en-us/uwp/api/windows.applicationmodel.fulltrustprocesslauncher

Upvotes: 2

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