asp.net控件开发基础(5)

完成基本复合控件基本呈现
(1)首先你要熟悉以下的属性和方法
Control.CreateChildControls 方法用于创建子控件
Control.EnsureChildControls 方法用于确认是否已创建子控件,如果未创建完成的话则调用CreateChildControls 方法创建子控件
Control.ChildControlsCreated 属性 获取一个值,是否已创建子控件

(2)了解并实现INamingContainer接口
用户控件UserControl类则继承了INamingContainer接口,确包保子控件具有唯一的ID名称,那复合控件也需要实现这个接口达到一样的目的,这个是值得注意的地方.复合控件以类撰写的方法来添加控件即CreateChildControls 方法

 

using System;
using System.Collections.Generic;
using System.Text;
using System.Web.UI.WebControls;
using System.Web.UI;
using System.ComponentModel;

namespace ComponentControl
{
    public class Ctrl9:WebControl,INamingContainer
    {
        private Label m_NameLabel = new Label();
        private Label m_PwdLabel = new Label();
        private TextBox m_NameTextBox = new TextBox();
        private TextBox m_PwdTextBox = new TextBox();
        private Button m_Button = new Button();
        private RequiredFieldValidator m_NameValidator = new RequiredFieldValidator();
        private RequiredFieldValidator m_PwdValidator = new RequiredFieldValidator();


        /**//// <summary>
        /// 重写Controls的get属性,保证在访问复合控件的子控件时子控件已经被创建
        /// EnsureChildControls()方法检查子控件是否被创建,如果没有被创建,
        /// 将自动调用CreateChildControls()方法来创建子控件
        /// </summary>
        public override ControlCollection Controls
        {
            get
            {
                EnsureChildControls();
                return base.Controls;
            }
        }

        CreateChildControls#region CreateChildControls

        protected override void CreateChildControls()
        {
            Controls.Clear();

            m_NameLabel.ID = "NameLabelID";
            m_NameLabel.Text = "Label1";

            m_PwdLabel.ID = "PwdLabelID";
            m_PwdLabel.Text = "Label2";

            m_NameTextBox.ID = "NameTextBoxID";

            m_PwdTextBox.TextMode = TextBoxMode.Password;
            m_PwdTextBox.ID = "PwdTextBoxID";

            m_Button.ID = "ButtonID";
            m_Button.Text = "Button1";

            m_NameValidator.ID = "Validator1";
            m_NameValidator.ErrorMessage = "请输入用户名";
            m_NameValidator.ControlToValidate = m_NameTextBox.ID;
            m_NameValidator.Text = "*";

            m_PwdValidator.ID = "Validator2";
            m_PwdValidator.ErrorMessage = "请输入密码";
            m_PwdValidator.ControlToValidate = m_PwdTextBox.ID;
            m_PwdValidator.Text = "*";

            Controls.Add(m_NameLabel);
            Controls.Add(m_PwdLabel);
            Controls.Add(m_NameTextBox);
            Controls.Add(m_PwdTextBox);
            Controls.Add(m_Button);
            Controls.Add(m_NameValidator);
            Controls.Add(m_PwdValidator);
        }

        #endregion

        Properties#region Properties

        [Description("Button显示的文本")]
        public string ButtonText
        {
            get
            {
                return m_Button.Text;
            }
            set
            {
                m_Button.Text = value;
            }
        }

        [Description("NameLabel显示的文本")]
        public string NameLabelText
        {
            get
            {
                return m_NameLabel.Text;
            }
            set
            {
                m_NameLabel.Text = value;
            }
        }

        [Description("PwdLabel显示的文本")]
        public string PwdLabelText
        {
            get
            {
                return m_PwdLabel.Text;
            }
            set
            {
                m_PwdLabel.Text = value;
            }
        }

        [Description("用户名")]
        public string Name
        {
            get { return m_NameTextBox.Text; }
            set { m_NameTextBox.Text = value; }
        }

        [Description("密码")]
        public string Pwd
        {
            get { return m_PwdTextBox.Text; }
        }

        #endregion

        Render#region Render

        protected override void Render(HtmlTextWriter writer)
        {
            writer.RenderBeginTag(HtmlTextWriterTag.Table);

            writer.RenderBeginTag(HtmlTextWriterTag.Tr);
            writer.RenderBeginTag(HtmlTextWriterTag.Td);
            m_NameLabel.RenderControl(writer);
            writer.RenderEndTag();
            writer.RenderBeginTag(HtmlTextWriterTag.Td);
            m_NameTextBox.RenderControl(writer);
            writer.RenderEndTag();
            writer.RenderBeginTag(HtmlTextWriterTag.Td);
            m_NameValidator.RenderControl(writer);
            writer.RenderEndTag();
            writer.RenderEndTag();

            writer.RenderBeginTag(HtmlTextWriterTag.Tr);
            writer.RenderBeginTag(HtmlTextWriterTag.Td);
            m_PwdLabel.RenderControl(writer);
            writer.RenderEndTag();
            writer.RenderBeginTag(HtmlTextWriterTag.Td);
            m_PwdTextBox.RenderControl(writer);
            writer.RenderEndTag();
            writer.RenderBeginTag(HtmlTextWriterTag.Td);
            m_PwdValidator.RenderControl(writer);
            writer.RenderEndTag();
            writer.RenderEndTag();

            writer.RenderBeginTag(HtmlTextWriterTag.Tr);
            writer.AddAttribute(HtmlTextWriterAttribute.Cols, "3");
            writer.AddAttribute(HtmlTextWriterAttribute.Align, "center");
            writer.RenderBeginTag(HtmlTextWriterTag.Td);
            m_Button.RenderControl(writer);
            writer.RenderEndTag();
            writer.RenderEndTag();

            writer.RenderEndTag();
        }

        #endregion
    }
}