[ControlBuilderAttribute(typeof(ImportFilesControlBuilder)),
 ParseChildren(false),  //true,"ColumnNames"
 PersistChildren(false),
// Designer(typeof(ImportFilesDesigner))
 ]
 public class ImportFiles: System.Web.UI.Control, INamingContainer, IPostBackEventHandler
 {
  private TextItemCollection _columnnames = new TextItemCollection();

[Category("General ImportFiles Parameters"),
  DesignerSerializationVisibility(DesignerSerializationVisibility.Content),
  PersistenceMode(PersistenceMode.InnerDefaultProperty),
  NotifyParentProperty(true),
  Description("The name of the import excel file colum")]
  public TextItemCollection ColumnNames
  {
   get
   { 
    return this._columnnames;
   }
   set
   {
    if (this._columnnames != value)
    {
     this._columnnames = value;
    }
   }
  }

}

    /// <summary>
    /// Summary description for TextItemCollection.
    /// </summary>
    [Editor(typeof(Asus.Helper.Component.WebControls.Design.ItemDataCollectionEditor),typeof(UITypeEditor)),
    Serializable]
    public class TextItemCollection: CollectionBase//, IStateManager
    {
        private TextItemCollection _testItems;

//        private bool _isTrackingViewState;
//        private bool _saveAll;

        public TextItemCollection Items
        { 
            get { return this._testItems; }
            set { this._testItems = value; } 
        }

        public TextItem this[int index]
        { 
            get 
            {
                return (TextItem)base.List[index];
            } 
        }

        public TextItemCollection()
        {
            //
            // TODO: Add constructor logic here
            //
        }

        Realize IStateManager Interface IStateManager Implementation

        public void Add(TextItem item) 
        { 
            base.List.Add(item); 
        }

        public int IndexOf(TextItem item) 
        { 
            return base.List.IndexOf(item); 
        }

        public void Remove(TextItem item)
        {
            base.List.Remove(item);
        }

        public bool Contains(TextItem item)
        {
            return base.List.Contains(item);
        }

        public void Insert(int index, TextItem item)
        {
            base.List.Insert(index,item);
        }

        public void CopyTo(Array array, int index)
        {
            base.List.CopyTo(array,index);
        }
    }