SelectedItem::Name Property

public void CodeExample(DTE2 dte)
{  
    try
    {
        // Open project and select one or more items in the
        // solution explorer before running this example.
        SelectedItem selItem;
        string msg = "";
        if (dte.SelectedItems.Count > 0)
        {
            selItem = dte.SelectedItems.Item(1);
            msg = "The first selected item is " + selItem.Name;
        }
        MessageBox.Show(msg);
    }
    catch(Exception ex)
    {
        MessageBox.Show(ex.Message);
    }
}