How to: Write Text to Files with a StreamWriter in Visual Basic
.NET Framework Security
This example creates a new file, if the file does not already exist. If an application needs to create a file, that application needs Create access for the folder. If the file already exists, the application needs only Write access, a lesser privilege. Where possible, it is more secure to create the file during deployment, and only grant Read access to a single file, rather than Create access for a folder.