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ASP.NET用户控件：增强型CheckBoxList控件

编辑:dnawo 日期:2008-09-14

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.NET的CheckBoxList控件允许进行多项选择，但是其SelectedValue属性值却只能取到第一个选择项的值，如果要获取全部选择项的值必须遍历各项判断选中再获取，同样你也无法一次设置多个项为选中状态，比较麻烦。下边我们重新创建一个CheckBoxList控件，他继承于CheckBoxList类，增加了两个属性NewSelectedText和NewSelectedValue，可一次性设置或获取CheckBoxList实例全部选择项的Text和Value值。

自定义CheckBoxList控件源码

打开Microsoft Visual Studio 2005，在类库中添加新项，选择"Web 自定义控件"，名称为CheckBoxList.cs：

复制内容到剪贴板程序代码 程序代码
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 MzwuCom.UI
{
    /// <summary>
    /// 多项选择复选框组
    /// </summary>
    [DefaultProperty("Text")]
    [ToolboxData("<{0}:CheckBoxList runat=server></{0}:CheckBoxList>")]
    public class CheckBoxList : System.Web.UI.WebControls.CheckBoxList
    {
        private const char SEPARATOR = '|';//分隔符

        /// <summary>
        /// 选中项的Text值
        /// </summary>
        [Browsable(false)]
        [DefaultValue("")]
        public string NewSelectedText
        {
            set
            {
                if (value != null && value != string.Empty && value != "")
                {
                    //取消原先选择项
                    //for (int i = 0; i < this.Items.Count; i++)
                    //{
                    //    this.Items[i].Selected = false;
                    //}
                    this.SelectedIndex = -1;
                    //重新选择
                    string[] textList = value.Split(new char[] { SEPARATOR });
                    for (int i = 0; i < textList.Length; i++)
                    {
                        for (int j = 0; j < this.Items.Count; j++)
                        {
                            if (this.Items[j].Text == textList[i])
                            {
                                this.Items[j].Selected = true;
                            }
                        }
                    }
                }
            }
            get
            {
                string textList = string.Empty;
                for (int i = 0; i < this.Items.Count; i++)
                {
                    if (this.Items[i].Selected == true)
                    {
                        textList += this.Items[i].Text + SEPARATOR.ToString();
                    }
                }
                if (textList != string.Empty)
                {
                    return textList.Substring(0, textList.Length - 1);
                }
                else
                {
                    return textList;
                }
            }
        }

        /// <summary>
        /// 属性:选中项的Value值
        /// </summary>
        [Browsable(false)]
        [DefaultValue("")]
        public string NewSelectedValue
        {
            set
            {
                if (value != null && value != string.Empty && value != "")
                {
                    //取消原先选择项
                    //for (int i = 0; i < this.Items.Count; i++)
                    //{
                    //    this.Items[i].Selected = false;
                    //}
                    this.SelectedIndex = -1;
                    //重新选择
                    string[] valueList = value.Split(new char[] { SEPARATOR });
                    for (int i = 0; i < valueList.Length; i++)
                    {
                        for (int j = 0; j < this.Items.Count; j++)
                        {
                            if (this.Items[j].Value == valueList[i])
                            {
                                this.Items[j].Selected = true;
                            }
                        }
                    }
                }
            }
            get
            {
                string valueList = string.Empty;
                for (int i = 0; i < this.Items.Count; i++)
                {
                    if (this.Items[i].Selected == true)
                    {
                        valueList += this.Items[i].Value + SEPARATOR.ToString();
                    }
                }
                if (valueList != string.Empty)
                {
                    return valueList.Substring(0, valueList.Length - 1);
                }
                else
                {
                    return valueList;
                }
            }
        }
    }
}

生成后在工具箱就能看到他了：



使用示例

Test.aspx:
复制内容到剪贴板程序代码 程序代码
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Test.aspx.cs" Inherits="Test" %>

<%@ Register Assembly="MzwuCom.UI" Namespace="MzwuCom.UI" TagPrefix="cc1" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>.NET自定义控件：增强型CheckBoxList控件-Mzwu.Com</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <cc1:checkboxlist id="CheckBoxList1" runat="server" repeatcolumns="4" RepeatDirection="Horizontal"><asp:ListItem Value="1">选项1</asp:ListItem>
            <asp:ListItem Value="2">选项2</asp:ListItem>
            <asp:ListItem Value="3">选项3</asp:ListItem>
            <asp:ListItem Value="4">选项4</asp:ListItem>
            <asp:ListItem Value="5">选项5</asp:ListItem>
            <asp:ListItem Value="6">选项6</asp:ListItem>
            <asp:ListItem Value="7">选项7</asp:ListItem>
            <asp:ListItem Value="8">选项8</asp:ListItem>
        </cc1:checkboxlist>
        <asp:Button ID="Button1" runat="server" Text="Set NewSelectedText" OnClick="Button1_Click" />
        <br />
        <asp:Button ID="Button2" runat="server" Text="Get NewSelectedText" OnClick="Button2_Click" />
        <br />
        <asp:Button ID="Button3" runat="server" Text="Set NewSelectedValue" OnClick="Button3_Click" />
        <br />
        <asp:Button ID="Button4" runat="server" Text="Get NewSelectedValue" OnClick="Button4_Click" /><br />
        <br />
        <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
    </div>
    </form>
</body>
</html>

Test.aspx.cs:

复制内容到剪贴板程序代码 程序代码
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using MzwuCom.UI;

public partial class Test : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        //
    }

    /// <summary>
    /// Set NewSelectedText
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void Button1_Click(object sender, EventArgs e)
    {

        CheckBoxList1.NewSelectedText = "选项1|选项3|选项5|选项7";
        Label1.Text = "Set NewSelectedText: " + CheckBoxList1.NewSelectedText;
    }

    /// <summary>
    /// Get NewSelectedText
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void Button2_Click(object sender, EventArgs e)
    {
        Label1.Text = "Get NewSelectedText: " + CheckBoxList1.NewSelectedText;
    }

    /// <summary>
    /// Set NewSelectedValue
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void Button3_Click(object sender, EventArgs e)
    {
        CheckBoxList1.NewSelectedValue = "2|4|6|8";
        Label1.Text = "Set NewSelectedValue: " + CheckBoxList1.NewSelectedValue;
    }

    /// <summary>
    /// Get NewSelectedValue
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void Button4_Click(object sender, EventArgs e)
    {
        Label1.Text = "Get NewSelectedValue: " + CheckBoxList1.NewSelectedValue;
    }
}


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