writer.RenderBeginTag(HtmlTextWriterTag.Input);

 public class CompositeLogin : WebControl, INamingContainer
    {

        private Button _button;
        private TextBox _nameTextBox;
        private Label _nameLabel;
        private TextBox _passwordTextBox;
        private Label _passwordLabel;
        private RequiredFieldValidator _nameValidator;
        private RequiredFieldValidator _passwordValidator;

        属性#region 属性
        [
        Bindable(true),
        Category("Appearance"),
        DefaultValue(""),
        Description("按钮文本")
        ]
        public string ButtonText
        {
            get
            {
                EnsureChildControls();
                return _button.Text;
            }
            set
            {
                EnsureChildControls();
                _button.Text = value;
            }
        }

        [
        Bindable(true),
        Category("Default"),
        DefaultValue(""),
        Description("姓名")
        ]
        public string Name
        {
            get
            {
                EnsureChildControls();
                return _nameTextBox.Text;
            }
            set
            {
                EnsureChildControls();
                _nameTextBox.Text = value;
            }
        }

        [
        Bindable(true),
        Category("Appearance"),
        DefaultValue(""),
        Description(
            "必须输入姓名")
        ]
        public string NameErrorMessage
        {
            get
            {
                EnsureChildControls();
                return _nameValidator.ErrorMessage;
            }
            set
            {
                EnsureChildControls();
                _nameValidator.ErrorMessage = value;
                _nameValidator.ToolTip = value;
            }
        }

        [
        Bindable(true),
        Category("Apperance"),
        DefaultValue(""),
        Description("姓名标签")
        ]
        public string NameLabel
        {
            get
            {
                EnsureChildControls();
                return _nameLabel.Text;
            }
            set
            {
                EnsureChildControls();
                _nameLabel.Text = value;

            }
        }

        [
        Browsable(false),
        DesignerSerializationVisibility(
            DesignerSerializationVisibility.Hidden)
        ]
        public string Password
        {
            get
            {
                EnsureChildControls();
                return _passwordTextBox.Text;
            }
        }

        [
        Bindable(true),
        Category("Appearance"),
        DefaultValue(""),
        Description(
            "必须输入密码")
        ]
        public string PasswordErrorMessage
        {
            get
            {
                EnsureChildControls();
                return _passwordValidator.ErrorMessage;
            }
            set
            {
                EnsureChildControls();
                _passwordValidator.ErrorMessage = value;
                _passwordValidator.ToolTip = value;
            }
        }

        [
        Bindable(true),
        Category("Appearance"),
        DefaultValue(""),
        Description("密码标签")
        ]
        public string PasswordLabel
        {
            get
            {
                EnsureChildControls();
                return _passwordLabel.Text;
            }
            set
            {
                EnsureChildControls();
                _passwordLabel.Text = value;

            }
        }
        #endregion Properties delegated to child controls

        方法#region 方法
        //撰写
        protected override void CreateChildControls()
        {
            Controls.Clear();

            _nameLabel = new Label();

            _nameTextBox = new TextBox();
            _nameTextBox.ID = "nameTextBox";

            _nameValidator = new RequiredFieldValidator();
            _nameValidator.ID = "validator1";
            _nameValidator.ControlToValidate = _nameTextBox.ID;
            _nameValidator.Text = "*";
            _nameValidator.Display = ValidatorDisplay.Static;

            _passwordLabel = new Label();

            _passwordTextBox = new TextBox();
            _passwordTextBox.TextMode = TextBoxMode.Password;
            _passwordTextBox.ID = "passwordTextBox";

            _passwordValidator = new RequiredFieldValidator();
            _passwordValidator.ID = "validator2";
            _passwordValidator.ControlToValidate = _passwordTextBox.ID;
            _passwordValidator.Text = "*";
            _passwordValidator.Display = ValidatorDisplay.Static;

            _button = new Button();
            _button.ID = "button1";

            this.Controls.Add(_nameLabel);
            this.Controls.Add(_nameTextBox);
            this.Controls.Add(_nameValidator);
            this.Controls.Add(_passwordLabel);
            this.Controls.Add(_passwordTextBox);
            this.Controls.Add(_passwordValidator);
            this.Controls.Add(_button);
        }

        //布局
        protected override void Render(HtmlTextWriter writer)
        {
            AddAttributesToRender(writer);

            writer.AddAttribute(HtmlTextWriterAttribute.Cellpadding,
                "1", false);
            writer.RenderBeginTag(HtmlTextWriterTag.Table);

            writer.RenderBeginTag(HtmlTextWriterTag.Tr);
            writer.RenderBeginTag(HtmlTextWriterTag.Td);
            _nameLabel.RenderControl(writer);
            writer.RenderEndTag();  // Td
            writer.RenderBeginTag(HtmlTextWriterTag.Td);
            _nameTextBox.RenderControl(writer);
            writer.RenderEndTag();  // Td
            writer.RenderBeginTag(HtmlTextWriterTag.Td);
            _nameValidator.RenderControl(writer);
            writer.RenderEndTag();  // Td
            writer.RenderEndTag();  // Tr

            writer.RenderBeginTag(HtmlTextWriterTag.Tr);
            writer.RenderBeginTag(HtmlTextWriterTag.Td);
            _passwordLabel.RenderControl(writer);
            writer.RenderEndTag();  // Td
            writer.RenderBeginTag(HtmlTextWriterTag.Td);
            _passwordTextBox.RenderControl(writer);
            writer.RenderEndTag();  // Td
            writer.RenderBeginTag(HtmlTextWriterTag.Td);
            _passwordValidator.RenderControl(writer);
            writer.RenderEndTag();  // Td
            writer.RenderEndTag();  // Tr

            writer.RenderBeginTag(HtmlTextWriterTag.Tr);
            writer.AddAttribute(HtmlTextWriterAttribute.Colspan, "2");
            writer.AddAttribute(HtmlTextWriterAttribute.Align, "right");
            writer.RenderBeginTag(HtmlTextWriterTag.Td);
            _button.RenderControl(writer);
            writer.RenderEndTag();  // Td
            writer.RenderBeginTag(HtmlTextWriterTag.Td);
            writer.Write(" ");
            writer.RenderEndTag();  // Td
            writer.RenderEndTag();  // Tr

            writer.RenderEndTag();  // Table
        }
        #endregion Overriden methods
    }