SelectionSet selectionSet = new SelectionSet();
StorableObject[] storableObjects = selectionSet.Selection;
if (storableObjects.Length == 0)
{
    Console.Out.WriteLine("No current selection!");
    return;
}
else
{
    Console.Out.WriteLine("Current selection contains of:");
    foreach (StorableObject so in storableObjects)
    {
        Console.Out.WriteLine("Object type: " + so.GetType().ToString());
    }
}

SelectionSet selectionSet = new SelectionSet();
//If any selected object will be changed, LockProjectByDefault must be set to true before obtaining any object
selectionSet.LockProjectByDefault = true;
Project oProject = selectionSet.GetCurrentProject(false);
oProject.ProjectName = "new_name";