如何在Windows窗体应用程序中保存文本文件

Question

I am creating a windows form application. for security reason i want to store licence information into a text file and want to encrypt it.

var serializer = new XmlSerializer(typeof(Licence));

var saveData = new Licence
{
    ProductId = txtProductID.Text,

    ProductKey = txtProductKey.Text,

    CreatedDate = validate.CreationDate,

    ExpireDate = validate.ExpireDate,

    DaysLeft = validate.DaysLeft
};

using (var writeFile = File.OpenWrite("data.txt"))
{
    serializer.Serialize(writeFile, saveData);
}

using this code i can able to create text file successfully. but when i publish this project and install it it gives me error. error message is...

Access to the path "C:\\Program Files (x86)\\WebenixSystem\\Metro Whole Sale\\data.txt" is denied.

************** Exception Text ************** System.UnauthorizedAccessException: Access to the path 'C:\\Program Files (x86)\\WebenixSystem\\Metro Whole Sale\\data.txt' is denied.

How can i resolve this issue, and how can i encrypt this txt file? please help...

Answer 1

As the error suggests - you do not have permission to access the path you are trying to save the file to.
As the file will be encrypted, you do not have to hide it. Therefore, you could save it in the documents folder of the users account.

Using this line of code will return the path to the 'My Documents' folder. You can create a new folder within there or save the file directly to this path.

Note this is a relative path so it will work for all users.

String pathToDocuments = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);

Answer 2

Also to note: The license information won't be shared between different users. If user will logon with different account, the license data won't be found, because each user has its own "MyDocuments", "AppData" etc...