Databoundcontrol support template [It is similar with Repeater control]

The purpose of this essay is recording the key steps if you hope to create control and hope it support template and edit the templates at designer time.

1. create a class derives from control class, inamecontainer, idataitemcontainer. this step is a little same as repeatitem (it is an instance to bind data that you can iterate datasource ). such as follows:

   [ToolboxItem(false)]    public class myItem :Control, IDataItemContainer    {        private object _currentItem;        private int _itemIndex;        public myItem(int itemIndex,object item)        {            _itemIndex = itemIndex;            _currentItem = item;        }        #region IDataItemContainer Members        public object DataItem        {            get { return _currentItem; }        }        public int DataItemIndex        {            get { return _itemIndex; }        }        public int DisplayIndex        {            get { return _itemIndex; }        }        #endregion    }

2. OverridePerformdatabindingMethod to bind data from datasource and present the data with the instance of myitem class.

  protected override void PerformDataBinding(IEnumerable data)        {            this.Controls.Clear();                createTemplateControls(TemplateType.HeaderTemplate, -1, null);                if (DataSource != null)                {                    IEnumerator iList = data.GetEnumerator();                    int index = 0;                    while (iList.MoveNext())                    {                        myItem itemObj = createTemplateControls(TemplateType.ItemTemplate, index, iList.Current);                        ItemEventArgs arg = new ItemEventArgs(itemObj);                        this.OnDataBound(arg);//Raise Event                        itemObj.DataBind();//Raise DataBind() so that all the controls in Template support databinder.                        index += 1;                    }                }                createTemplateControls(TemplateType.FootTemplate, -2, null);        }             private myItem createTemplateControls(TemplateType type,int itemIndex,object currentItem)        {            ITemplate template = null;            switch (type)            {                case TemplateType.HeaderTemplate:                    template = HeaderTemplate;                    break;                case TemplateType.ItemTemplate:                    template = ItemTemplate;                    break;                case TemplateType.FootTemplate:                    template = FootTemplate;                    break;                default:                    template = HeaderTemplate;                    break;            }            myItem headItem = null;            if (template != null)            {                headItem = new myItem(itemIndex, currentItem);                template.InstantiateIn(headItem);                this.Controls.Add(headItem);            }            return headItem;        }    }

3. To support editable template at designer time, we 'd better to create particle controldesigner.

 public class MyRepeaterDesigner : DataBoundControlDesigner    {        public override void Initialize(IComponent component)        {            base.Initialize(component);            SetViewFlags(ViewFlags.TemplateEditing, true);        }        public override string GetDesignTimeHtml()        {            MyRepeater control = Component as MyRepeater;            if (control != null)            {                if (control.ItemTemplate == null)                {                    return CreatePlaceHolderDesignTimeHtml("You can go through the 'Righ click' or click the 'Smart tag' to edit 'Item/Header/Foot template '");                }            }            return base.GetDesignTimeHtml();        }        TemplateGroupCollection templateGroups;        public override TemplateGroupCollection TemplateGroups        {            get            {                if (templateGroups == null)                {                    templateGroups = base.TemplateGroups;                    TemplateGroup head_template = new TemplateGroup("HeaderTemplate");                    head_template.AddTemplateDefinition(new TemplateDefinition(this, "Header", Component, "HeaderTemplate", false));                    templateGroups.Add(head_template);                    TemplateGroup item_template = new TemplateGroup("ItemTemplate");                    item_template.AddTemplateDefinition(new TemplateDefinition(this, "Item", Component, "ItemTemplate", false));                    templateGroups.Add(item_template);                    TemplateGroup foot_template = new TemplateGroup("FootTemplate");                    foot_template.AddTemplateDefinition(new TemplateDefinition(this, "Foot", Component, "FootTemplate", false));                    templateGroups.Add(foot_template);                }                return templateGroups;            }        }    }

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