Unauthorized Access Exception in Windows 7

Question

Hello,

I have an application which reads a license file when it starts up. My install creates the folder in Program Files for the application, creates the license folder and puts the license file in there. However when I try and run the application, it needs to read/update the license file. When I try and do that I get an "Unauthorized Access Exception". I am logged on as an administrator and I'm running the program manually.

Any idea why I cannot access that file even though the path is correct? But in the install it creates the file and folder just fine?

I have MyApplication.exe, and my license reader is in a seperate DLL called MyApplicationTools. I am reading/write the license file like so:

       //Read
       StreamReader reader = new StreamReader(path + "license.lic");

       //Write
       StreamWriter writer2 = new StreamWriter(path + "License.lic");
       string str = Convert.ToBase64String(sharedkey.Key);
       writer2.WriteLine(str);
       writer2.Close();

Thanks

Answer 1

Because of UAC, your program isn't getting administrative privileges.

Right-click the program, click Run as Administrator, and try again.
You can also create a manifest that tells Windows to always run as Administrator.
However, you should consider putting the license file in the user's AppData folder, which does not require administrative privileges.

---

By the way, you should use the Path.Combine method to create paths.
Also, if you just want to write a single string to a file, you should call File.WriteAllText.
For example:

File.WriteAllText(Path.Combine(path, "License.lic"), Convert.ToBase64String(sharedkey.Key));

Answer 2

You need to put writable files in a User application folder - Program Files is not writable by ordinary users. Iirc, on Win7 the default location is C:\Users\[username]\AppData\[appname]. You shouldn't be running as administrator just to write into Program Files.

Answer 3

Use AppData instead. There is an environment variable for this. You can see this by going into explorer and typing %appdata%. It'll take you to the appropriate folder. To access this in C# I've written the following function.

    /// <summary>
    /// Gets the path where we store Application Data.
    /// </summary>
    /// <returns>The Application Data path</returns>
    public static string GetAppDataPath()
    {
        string dir = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData);
        dir = System.IO.Path.Combine(dir, "MyCompany\\MyApplication");
        if (!System.IO.Directory.Exists(dir))
        {
            System.IO.Directory.CreateDirectory(dir);
        }

        return dir;
    }