复合自定义控件实例：Login控件

Login
using System;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.ComponentModel;
using System.Drawing;


namespace Login
{
    /**//// <summary>
    /// WebCustomControl1 的摘要说明。
    /// </summary>
    [DefaultProperty("BackColor"),
    ToolboxData("<{0}:LoginCtrl runat=server></{0}:LoginCtrl>")]
    
    public class LoginCtrl : System.Web.UI.WebControls.WebControl
    {
        private Color _fontColor = Color.Black;//声明字体颜色变量
        private Color _backColor = Color.White;//声明控件背景变量

        //首先声明要在复合控件中使用的子控件。
        private Label lblUserName = new Label();//显示“用户名”的Label控件
        private Label lblPassWord = new Label();//显示“密码”的Label控件
        private TextBox txtUserName = new TextBox();//用户名输入的TextBox控件
        private TextBox txtPassWord = new TextBox();//密码输入的TextBox控件
        private Button submitButton = new Button();//提交Button控件
        private Button clearButton = new Button();//重置Button控件
        private System.Web.UI.WebControls.Panel pnlFrame = new System.Web.UI.WebControls.Panel();//承载其它控件的容器Panel控件

        //当然要在符合控件中使用的事件一定要声明的，它们会出现在属性框的事件栏里。
        public event EventHandler SubmitOnClick;//声明自定义控件LoginCtrl的提交事件
        public event EventHandler ClearOnClick;//声明自定义控件LoginCtrl的重置事件

        public LoginCtrl() 

        {

            //刚刚声明的子控件和事件要在这里进行初始化处理。

            //初始化控件的属性

            this.lblUserName.Text = "用户名:";
            this.lblPassWord.Text = "密  码:";
            this.txtPassWord.TextMode = System.Web.UI.WebControls.TextBoxMode.Password;
            this.pnlFrame.Width = 240;
            this.pnlFrame.Height = 120;
            this.pnlFrame.BackColor = Color.Empty;

            //添加提交按钮点击事件
            submitButton.Text = "确定";
            submitButton.Click += new EventHandler(this.SubmitBtn_Click);

            //添加重置按钮点击事件
            clearButton.Text = "重置";
            clearButton.Click += new EventHandler(this.ClearBtn_Click);

            //将声明的各子控件添加到LoginCtrl中
            this.Controls.Add(this.submitButton);
            this.Controls.Add(this.clearButton);
            this.Controls.Add(this.txtUserName);
            this.Controls.Add(this.txtPassWord);
            this.Controls.Add(this.lblUserName);
            this.Controls.Add(this.lblPassWord);
            this.Controls.Add(this.pnlFrame);
        }

        //根据自己的需要添加或重载符合控件的公共属性
        //字体颜色属性

        [Bindable(false), 
        Category("Appearance"), 
        DefaultValue("")] 

        public override Color ForeColor 
        {
            get
            {
                return this._fontColor;
            }
            set
            {
                this._fontColor = value;
            }
        }

        //控件背景属性

        [Bindable(false), 
        Category("Appearance"), 
        DefaultValue("")] 
        public override Color BackColor 
        {
            get
            {
                return this._backColor;
            }
            set
            {
                this._backColor = value;
            }
        }

        //用户名属性

        [Bindable(false),
        Category("Appearance"),
        DefaultValue("")] 

        public string UserName
        {
            get
            {
                return this.txtUserName.Text;
            }
            set
            {
                this.txtUserName.Text = value;
            }
        }

        //密码属性

        [Bindable(false),
        Category("Appearance"),
        DefaultValue(""), Browsable(false)] 

        public string PassWord
        {
            get
            {
                return this.txtPassWord.Text;
            }
            set
            {
                this.txtPassWord.Text = value;
            }
        }

        //控件宽度属性

        [Bindable(false),
        Category("Appearance"),
        DefaultValue("")] 

        public override Unit Width
        {
            get
            {
                return this.pnlFrame.Width;
            }
            set
            {
                this.pnlFrame.Width = value;
            }
        }

        //控件高度属性

        [Bindable(false),
        Category("Appearance"),
        DefaultValue("")] 

        public override Unit Height
        {
            get
            {
                return this.pnlFrame.Height;
            }
            set
            {
                this.pnlFrame.Height = value;
            }
        }

        //控件边框颜色属性

        [Bindable(false),
        Category("Appearance"),
        DefaultValue("")] 

        public override Color BorderColor
        {
            get
            {
                return this.pnlFrame.BorderColor;
            }
            set
            {
                this.pnlFrame.BorderColor = value;
            }
        }

        //控件边框样式属性

        [Bindable(false),
        Category("Appearance"),
        DefaultValue("")] 

        public override BorderStyle BorderStyle
        {
            get
            {
                return this.pnlFrame.BorderStyle;
            }
            set
            {
                this.pnlFrame.BorderStyle = value;
            }
        }

        //控件边框宽度属性

        [Bindable(false),
        Category("Appearance"),
        DefaultValue("")] 

        public override Unit BorderWidth
        {
            get
            {
                return this.pnlFrame.BorderWidth;
            }
            set
            {
                this.pnlFrame.BorderWidth = value;
            }
        }

        //下面要把控件输出出去，展示在页面上。

        /**//// <summary> 
        /// 将此控件呈现给指定的输出参数。
        /// </summary>
        /// <param name="output"> 要写出到的 HTML 编写器 </param>

        protected override void Render(HtmlTextWriter output)
        {
            this.pnlFrame.RenderBeginTag(output);//输出Panel控件

            //在Panel中绘制表格
            output.AddAttribute(HtmlTextWriterAttribute.Border,"0");
            output.AddAttribute(HtmlTextWriterAttribute.Cellpadding,"0");
            output.AddAttribute(HtmlTextWriterAttribute.Cellspacing,"0");
            output.AddAttribute(System.Web.UI.HtmlTextWriterAttribute.Width,"100%");
            output.AddAttribute(System.Web.UI.HtmlTextWriterAttribute.Height,"100%");
            output.AddAttribute(HtmlTextWriterAttribute.Bgcolor,this._backColor.Name);
            output.RenderBeginTag(HtmlTextWriterTag.Table);
            output.RenderBeginTag(HtmlTextWriterTag.Tr);
            output.RenderBeginTag(HtmlTextWriterTag.Td);
            //在表格中添加Label控件
            this.lblUserName.ForeColor = this._fontColor;
            this.lblUserName.RenderControl(output);
            output.RenderEndTag();
            output.RenderBeginTag(HtmlTextWriterTag.Td);
            //在表格中添加TextBox控件
            this.txtUserName.RenderControl(output);
            output.RenderEndTag();
            output.RenderEndTag();
            output.RenderBeginTag(HtmlTextWriterTag.Tr);
            output.RenderBeginTag(HtmlTextWriterTag.Td);
            //在表格中添加Label控件
            this.lblPassWord.ForeColor = this._fontColor;
            this.lblPassWord.RenderControl(output);
            output.RenderEndTag();
            output.RenderBeginTag(HtmlTextWriterTag.Td);
            //在表格中添加TextBox控件
            this.txtPassWord.RenderControl(output);
            output.RenderEndTag();
            output.RenderEndTag();
            output.RenderBeginTag(HtmlTextWriterTag.Tr);
            output.AddAttribute(HtmlTextWriterAttribute.Align,"right");
            output.RenderBeginTag(HtmlTextWriterTag.Td);
            //在表格中添加Button控件
            this.submitButton.RenderControl(output);
            output.RenderEndTag();
            output.AddAttribute(HtmlTextWriterAttribute.Align,"center");
            output.RenderBeginTag(HtmlTextWriterTag.Td);
            //在表格中添加Button控件
            this.clearButton.RenderControl(output);
            output.RenderEndTag();
            output.RenderEndTag();
            output.RenderEndTag();
            this.pnlFrame.RenderEndTag(output);
        }

        //当按钮点击时怎么做呢？这是个事件冒泡。
        //处理提交按钮点击事件

        private void SubmitBtn_Click(object sender, EventArgs e)
        {
            EventArgs e1 = new EventArgs();
            if(this.SubmitOnClick!=null)
                this.SubmitOnClick(this.submitButton,e1);
        }

        //处理重置按钮点击事件

        private void ClearBtn_Click(object sender, EventArgs e)
        {
            this.txtPassWord.Text = "";
            this.txtUserName.Text = "";
            EventArgs e1 = new EventArgs();
            if(this.ClearOnClick!=null)
                this.ClearOnClick(this.clearButton,e1);
        }

    }

}