Question

I need to restrict access to my application to only one specific user account. I have found classes under WMI to find users accounts, but I don´t know how to recognize which one is running my app.

Answer 1

There are simpler ways to get the current username than using WMI.

WindowsIdentity.GetCurrent().Name will get you the name of the current Windows user.

Environment.Username will get you the name of the currently logged on user.

The difference between these two is that WindowsIdentity.GetCurrent().Name will also include the domain name as well as the username (ie. MYDOMAIN\adrian instead of adrian). If you need the domain name from Environment, you can use Environment.UserDomainName.

EDIT

If you really want to do it using WMI, you can do this:

ManagementObjectSearcher searcher = new ManagementObjectSearcher("SELECT UserName FROM Win32_ComputerSystem");
ManagementObjectCollection collection = searcher.Get();
string username = (string) collection.Cast<ManagementBaseObject>().First()["UserName"];

Unfortunately, there is no indexer property on ManagementObjectCollection so you have to enumerate it to get the first (and only) result.