C# 將容器的Contro屬性下控件的轉換成枚舉類型以便使用LINQ語句進行查詢

/// <summary>
/// 將容器的Contro屬性下控件的轉換成枚舉類型以便使用LINQ語句進行查詢
 /// </summary>
 /// <param name="container"></param>
 /// <returns></returns>
 public IEnumerable<Control> GetControls(Control container)
 {
     foreach (Control childControl in container.Controls)
     {   
         // Recurse child controls.
         foreach (var grandChild in GetControls(childControl))
             yield return grandChild;
         yield return childControl;
     }
 }