如何动态添加控件到指定位置?

Question

我是想开发一个服务器控件,该控件继承Panel类, 
我是想将Botton添加到"这里有内容"下面,不知道怎么实现? 
<cc1:FlowContral ID="FlowContral1" runat="server" Text="立即提交" OnButtonClick="SaveFlow">
这里有内容
</cc1:FlowContral>服务器控件代码如下: 
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Text;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;namespace test
{
    [DefaultProperty("Text")]
    [ToolboxData("<{0}:ServerControl1 runat=server></{0}:ServerControl1>")]
    public class FlowContral : Panel
    {
        //声明变量
        private Button _button;
        private static readonly object EventButtonClick = new object();
        private Style _buttonStyle;
        private Label _label;        //定义属性Text，用于指定按钮上的文字
        [
        Bindable(true),
        Category("Appearance"),
        DefaultValue(""),
        Description("获取或设置显示显示在按钮上的文字")
        ]
        public string Text
        {
            get
            {
                EnsureChildControls();
                return _button.Text;
            }
            set
            {
                EnsureChildControls();
                _button.Text = value;
            }
        }        //定义ButtonStyle属性
        [
        Category("Style"),
        Description("设置Button的样式属性"),
        DesignerSerializationVisibility(DesignerSerializationVisibility.Content),
        NotifyParentProperty(true),
        PersistenceMode(PersistenceMode.InnerProperty),
        ]
        public virtual Style ButtonStyle
        {
            get
            {
                if (_buttonStyle == null)
                {
                    _buttonStyle = new Style();
                    if (IsTrackingViewState)
                    {
                        ((IStateManager)_buttonStyle).TrackViewState();
                    }
                }
                return _buttonStyle;
            }
        }        //重写Controls属性
        public override ControlCollection Controls
        {
            get
            {
                EnsureChildControls();
                return base.Controls;
            }
        }
        //重写CreateChildControls方法，将子控件添加到复合控件中
        protected override void CreateChildControls()
        {
            Controls.Clear();
            _button = new Button();
            _label = new Label();
            _label.ID = "lab";
            _button.ID = "btn";
            _button.CommandName = "ButtonClick";
            this.Controls.Add(_button);
            this.Controls.Add(_label);
        }
        public event EventHandler ButtonClick
        {
            add
            {
                Events.AddHandler(EventButtonClick, value);
            }
            remove
            {
                Events.RemoveHandler(EventButtonClick, value);
            }
        }        protected virtual void OnButtonClick(EventArgs e)
        {
            EventHandler buttonClickHandler = (EventHandler)Events[EventButtonClick];
            if (buttonClickHandler != null)
            {
                buttonClickHandler(this, e);
            }
        }        protected override bool OnBubbleEvent(object sender, EventArgs e)
        {
            bool handled = false;
            if (e is CommandEventArgs)
            {
                CommandEventArgs ce = (CommandEventArgs)e;
                if (ce.CommandName == "ButtonClick")
                {
                    OnButtonClick(EventArgs.Empty);
                    handled = true;
                }
            }
            return handled;
        }
    }
}

Answer 1

先放一个容器控件，再动态的输出HTML脚本

Answer 2

用了种笨方法把问题解决了。protected override void Render(HtmlTextWriter writer)
        {
            Controls.Remove(_button);//先将button移出Controls集，这样输出就不会显示此button
            RenderContents(writer);//显示Panel内的内容
            writer.RenderBeginTag(HtmlTextWriterTag.Div);
            this.Controls.Add(_button);//必须再将button添加到Controls集，这样能才捕获到onclick的事件
            _button.RenderControl(writer);//显示button
            writer.RenderEndTag();
        }