Asp.net 基础7（自定义控件之验证与数据绑定）

验证，只须标记控件的属性为 ValidationProperty

    [ValidationProperty("Name")]

    public class NameControl : Control

    {}

数据绑定：

支持数据绑定的控件，首先对外有DataSource属性，还有DataTextField属性，在加上DataObject（用来表示绑定的对象）

重写基类的 OnDataBinding方法。这里还用到反射的一些方法。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Collections;
using System.Data;
using System.ComponentModel;
using System.Reflection;

namespace OwnControl
{
    public class DataBindControl:Control
    {
        //用来存放数据的ArrayList，这个也配合ViewState使用
        private ArrayList cacheList = new ArrayList();

        //要显示的字段
        private string dataTextField;

        [Category("自定义属性"),DefaultValue(""),Description("要显示的数据源的字段")] 
        public string DataTextField
        {
            set { this.dataTextField=value; }
            get { return this.dataTextField; }
        }

        //数据源
        private object dataSource;

        [Category("自定义属性"),Description("数据源")] 
        public object DataSource
        {
            set{ this.dataSource=value; }
            get{ return this.dataSource; }
        }

        private object dataObject;

        [Category("自定义属性"),Description("绑定数据对象")]
        public object DataObject
        {
            get { return dataObject; }
            set { dataObject = value; }
        }


        private IEnumerable GetResloverDataSource(object ds)
        {
            if (ds is IEnumerable)
                return (IEnumerable)ds;
            else if (ds is DataTable)
                return (IEnumerable)(((DataTable)ds).DefaultView);
            else if (ds is DataSet)
                return (IEnumerable)(((DataSet)ds).Tables[0].DefaultView);
            else if (ds is IList)
                return (IEnumerable)ds;
            else return null;
        }

        /// <summary>
        /// 从已转化为IEnumerable的数据源的一行中取出需要的DataTextField规定的数据
        /// </summary>
        /// <param name="item">已转化为IEnumerable的数据源的一行数据</param>
        /// <returns>取得的数据的string形式</returns>
        private string getDataItem(object item)
        {
            if (item is IDataRecord)
                return ((IDataRecord)item)[this.dataTextField].ToString();
            else if (item is DataRowView)
                return ((DataRowView)item)[this.dataTextField].ToString();
            else if (item.GetType().ToString() == dataObject.GetType().ToString())
                return GetObjetFiledValue(item, this.dataTextField);
            else return item.ToString();
        }

        private string GetObjetFiledValue(object obj, string fieldName)
        {
            Type dataType = obj.GetType();
            PropertyInfo bindField = dataType.GetProperty(fieldName);
            object bindvalue = bindField.GetValue(obj,null);
            return bindvalue.ToString();
        }

        /// <summary>
        /// 处理DataBinding事件，把数据源中需要的数据加到一个ArrayList中。
        /// </summary>
        /// <param name="e">EventArgs</param>
        protected override void OnDataBinding(EventArgs e)
        {
            base.OnDataBinding(e);
            if (this.dataSource != null)
            {
                //如果Count为0，则表示是第一次加载
                if (this.cacheList.Count == 0)
                {
                    IEnumerable source = this.GetResloverDataSource(this.dataSource);
                    IEnumerator item = source.GetEnumerator();
                    while (item.MoveNext())
                    {
                        //保存数据
                        this.cacheList.Add(this.getDataItem(item.Current));
                    }
                }
            }
        }

        /// <summary>
        /// 呈现，用遍历来循环输出ArrayList中的数据
        /// </summary>
        /// <param name="writer">HtmlTextWriter</param>
        protected override void Render(HtmlTextWriter writer)
        {
            foreach (string s in this.cacheList)
            {
                writer.RenderBeginTag(HtmlTextWriterTag.Div);
                writer.Write(s);
                writer.RenderEndTag();
            }
        }

        /// <summary>
        /// 保存自页回发到服务器后发生的任何服务器控件视图状态更改。
        /// </summary>
        /// <returns>返回服务器控件的当前视图状态。</returns>
        protected override object SaveViewState()
        {
            object[] vState = new object[3];
            vState[0]=base.SaveViewState();
            vState[1]=this.cacheList;
            vState[2] = this.dataObject;
            return vState;
        }

        /// <summary>
        ///从 SaveViewState 方法保存的上一个页请求还原视图状态信息。
        /// </summary>
        /// <param name="savedState">表示要还原的控件状态的 Object</param>
        protected override void LoadViewState(object savedState)
        {
            if (savedState != null)
            {
                object[] vState = (object[])savedState;
                if (vState[0] != null)
                    base.LoadViewState(vState[0]);
                if (vState[1] != null)
                    this.cacheList = (ArrayList)vState[1];
                if (vState[2] != null)
                    this.dataObject = vState[2];
            }
        }
    }
}

 界面使用的方法：

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="TestDataBindControlWebForm.aspx.cs" Inherits="TestCodeBehind.TestDataBindControlWebForm" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<%@ Register Namespace="OwnControl" TagPrefix="useown" Assembly="OwnControl" %>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>无标题页</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    <useown:DataBindControl ID="control" runat="server" DataTextField="Name" EnableViewState="true"></useown:DataBindControl>
    <asp:Button ID="btnOk" runat="server" Text="确定" onclick="btnOk_Click" />
    </div>
    </form>
</body>
</html>

后值的代码：
using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Collections.Generic;

namespace TestCodeBehind
{
    public partial class TestDataBindControlWebForm : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {

        }

        protected void btnOk_Click(object sender, EventArgs e)
        {
            List<Student> studentList=new List<Student>();
            for(int i=0;i<10;i++)
            {
                Student stu=new Student(i.ToString()+"name",i);
                studentList.Add(stu);
            }
            this.control.DataObject = new Student("",0);
            this.control.DataSource = studentList;
            this.control.DataBind();
        }
    }

    [Serializable]
    public class Student
    {
        public Student(string name,int age)
        {
            this.name = name;
            this.age = age;
        }
        private string name;

        public string Name
        {
            get { return name; }
            set { name = value; }
        }

        private int age;

        public int Age
        {
            get { return age; }
            set { age = value; }
        }

    }
}