Ext.Net.TabPanel.Render C# (CSharp) Method

        protected override void Render(HtmlTextWriter writer)
        {
            if (this.ActiveTabIndex >= this.Items.Count && this.Page != null && !this.Page.IsPostBack && !(RequestManager.IsAjaxRequest && !this.IsDynamic))
            {
                string msg = string.Format("The .ActiveTabIndex value was set to the index of an item which does not exist in the '{0}' Items Collection.{3}The .ActiveTabIndex can not be set to a value > {1}.{3}The actual .ActiveTabIndex Value attempted was {2}.{3}{3}Are you dynamically creating Components and attempting to set the .ActiveTabIndex property to the index of an item which was dynamically created? If yes, please ensure your Compoennts are recreated on each request.{3}{3}COMMON CAUSE: Setting the .ActiveTabIndex to the index of an item which was created during a previous Button Click server-side Event.",
                        this.ID,
                        (this.Items.Count - 1).ToString(),
                        this.ActiveTabIndex.ToString(),
                        Environment.NewLine);
                
                throw new IndexOutOfRangeException(msg);
            }

            base.Render(writer);
        }