OnBubbleEvent冒泡事件奇怪的问题

今天没事试着写写控件，没想到碰到一个奇怪问题

public class myListView : CompositeDataBoundControl,INamingContainer 
    {
         private int editIndex = -1;
        [Category("Default"), DefaultValue(-1)]
        public int EditIndex
        {
            get { return editIndex; }
            set { editIndex = value; }
        }

        //public int EditIndex
        //{
        //    get
        //    {
        //        if (ViewState["EditIndex"] == null)
        //        {
        //            return -1;
        //        }
        //        return (int)ViewState["EditIndex"];
        //    }
        //    set { ViewState["EditIndex"] = value; }
        //}

        #region 模板
        private ITemplate itemTemplate;
        [TemplateContainer(typeof(myListViewItem)), PersistenceMode(PersistenceMode.InnerProperty)]
        public ITemplate ItemTemplate
        {
            get { return itemTemplate; }
            set { itemTemplate = value; }
        }

        private ITemplate editTemplate;
        [TemplateContainer(typeof(myListViewItem), BindingDirection.TwoWay), PersistenceMode(PersistenceMode.InnerProperty)]
        public ITemplate EditTemplate
        {
            get { return editTemplate; }
            set { editTemplate = value; }
        }
        #endregion

        protected override int CreateChildControls(System.Collections.IEnumerable dataSource, bool dataBinding)
        {
            int index = 0;
            if (dataBinding)
            {

            }
            if (ItemTemplate != null)
            {
                Controls.Clear();
                foreach (object dataItem in dataSource)
                {
                    myListViewItem myItem = new myListViewItem(dataItem, index, index);
                    if (EditIndex == index)
                    {
                        if (EditTemplate != null)
                        {
                            EditTemplate.InstantiateIn(myItem);
                        }
                    }
                    else
                    {                      
                        ItemTemplate.InstantiateIn(myItem);
                    }
                    index++;
                    Controls.Add(myItem);
                }
            }
            DataBind(false);
            ChildControlsCreated = true;
            return index;
        }

        protected override HtmlTextWriterTag TagKey
        {
            get
            {
                return HtmlTextWriterTag.Ul;
            }
        }

        protected override bool OnBubbleEvent(object source, EventArgs args)
        {
            bool handle = false;
            if (args is CommandEventArgs)
            {
                CommandEventArgs myargs = args as CommandEventArgs;
                switch (myargs.CommandName.ToUpper())
                {
                    case "EDIT":
                        EditIndex = int.Parse( myargs.CommandArgument.ToString());
                        RequiresDataBinding = true;
                        handle=true;
                        break;
                    case "UPDATE":
                        break;
                    case "CANCEL":
                        EditIndex = -1;
                        RequiresDataBinding = true;
                        handle = true;
                        break;
                    default:
                        break;
                }
            }
            return handle;
        }
    }

[ToolboxItem(false)]
    public  class myListViewItem:WebControl,INamingContainer,IDataItemContainer
    {
        private object dataItem;
        private int dataIndex;
        private int index;


        public myListViewItem()
        {

        }

        public myListViewItem(object dataItem, int dataIndex, int index)
        {
            this.dataItem = dataItem;
            this.dataIndex = dataIndex;
            this.index = index;
        }

        #region IDataItemContainer 成员

        public object DataItem
        {
            get { return dataItem; }
        }

        public int DataItemIndex
        {
            get { return dataIndex; }
        }

        public int DisplayIndex
        {
            get { return index; }
        }

        #endregion


        protected override HtmlTextWriterTag TagKey
        {
            get
            {
                return HtmlTextWriterTag.Li;
            }
        }

        protected override bool OnBubbleEvent(object source, EventArgs args)
        {
            if (source is IButtonControl)
            {
                CommandEventArgs e = args as CommandEventArgs;
                if (e != null)
                {
                    CommandEventArgs myargs = new CommandEventArgs(e.CommandName, this.dataIndex.ToString());
                    base.RaiseBubbleEvent(this, myargs);
                    return true;
                }
            }
            return false;
        }
    }



源代码：
 <lv:myListView ID="myList" runat="server" DataSourceID="SqlDataSource1">
            <ItemTemplate>
                uid:
                <asp:Label ID="uidLabel" runat="server" Text='<%# Eval("uid") %>'></asp:Label><br />
                username:
                <asp:Label ID="usernameLabel" runat="server" Text='<%# Bind("username") %>'></asp:Label><br />
                nickname:
                <asp:Label ID="nicknameLabel" runat="server" Text='<%# Bind("nickname") %>'></asp:Label><br />
                <asp:LinkButton ID="EditButton" runat="server"  CommandName="Edit"
                    Text="编辑">
                </asp:LinkButton>
            </ItemTemplate>
            <EditTemplate>
                uid:
                <asp:Label ID="uidLabel1" runat="server" Text='<%# Eval("uid") %>'></asp:Label><br />
                username:
                <asp:TextBox ID="usernameTextBox" runat="server" Text='<%# Bind("username") %>'></asp:TextBox><br />
                nickname:
                <asp:TextBox ID="nicknameTextBox" runat="server" Text='<%# Bind("nickname") %>'></asp:TextBox><br />
                <asp:Button ID="aa" runat="server" Text="update"  CommandName="update"/>
               <asp:Button ID="bb" runat="server" Text="cancel"  CommandName="cancel"/>
            </EditTemplate>
        </lv:myListView>

当没有EditIndex属性没有加viewstate时，cancel和update都不会调用OnBubbleEvent事件，
EditIndex属性加了viewstate时，cancel和update会调用OnBubbleEvent事件