Yes, that's the correct way to do it. If you're looking to give yourself a "Clean" (or, as I'd prefer to call it, "Empty" function), you can create an extension method.
public static void Empty(this System.IO.DirectoryInfo directory)
{
foreach(System.IO.FileInfo file in directory.GetFiles()) file.Delete();
foreach(System.IO.DirectoryInfo subDirectory in directory.GetDirectories()) subDirectory.Delete(true);
}
This will then allow you to do something like..
System.IO.DirectoryInfo directory = new System.IO.DirectoryInfo(@"C:\...");
directory.Empty();