.net2.0 自定义CheckBoxList验证控件

时间：2010-09-27 来源：王培

转自：http://www.cnblogs.com/prolifes/articles/1385255.html

页面上有个CheckBoxList控件,用户必须选一个选项才能提交,现有的asp.net验证控件还不能验证CheckBoxList，怎么办?
1.新建CheckBoxListValidator类,继承BaseValidator

using System;
using System.Data;
using System.Configuration;
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 System.Text;

namespace CheckBoxListValidator
{
    public class CheckBoxListValidator : BaseValidator
    {
        protected override bool ControlPropertiesValid()
        {
            return true;
        }

        protected override bool EvaluateIsValid()
        {
            return EvaluateIsChecked();
        }

        protected bool EvaluateIsChecked()
        {
            CheckBoxList _cbl = ((CheckBoxList)FindControl(ControlToValidate));
            foreach (ListItem li in _cbl.Items)
            {
                if (li.Selected == true)
                {
                    return true;
                }
            }
            return false;
        }

        protected override void OnPreRender(EventArgs e)
        {
            if (EnableClientScript)
            {
                ClientScript();
            }
            base.OnPreRender(e);
        }

        protected void ClientScript()
        {
            Attributes["evaluationfunction"] = "cb_vefify";

            StringBuilder sb_Script = new StringBuilder();
            sb_Script.Append("<script language=\"javascript\">");
            sb_Script.Append("\r");
            sb_Script.Append("\r");
            sb_Script.Append("function cb_vefify(val) {");
            sb_Script.Append("\r");
            sb_Script.Append("var val = document.all[document.all[\"");
            sb_Script.Append(this.ClientID);
            sb_Script.Append("\"].controltovalidate];");
            sb_Script.Append("\r");
            sb_Script.Append("var col = val.all;");
            sb_Script.Append("\r");
            sb_Script.Append("if ( col != null ) {");
            sb_Script.Append("\r");
            sb_Script.Append("for ( i = 0; i < col.length; i++ ) {");
            sb_Script.Append("\r");
            sb_Script.Append("if (col.item(i).tagName == \"INPUT\") {");
            sb_Script.Append("\r");
            sb_Script.Append("if ( col.item(i).checked ) {");
            sb_Script.Append("\r");
            sb_Script.Append("\r");
            sb_Script.Append("return true;");
            sb_Script.Append("\r");
            sb_Script.Append("}");
            sb_Script.Append("\r");
            sb_Script.Append("}");
            sb_Script.Append("\r");
            sb_Script.Append("}");
            sb_Script.Append("\r");
            sb_Script.Append("\r");
            sb_Script.Append("\r");
            sb_Script.Append("return false;");
            sb_Script.Append("\r");
            sb_Script.Append("}");
            sb_Script.Append("\r");
            sb_Script.Append("}");
            sb_Script.Append("\r");
            sb_Script.Append("</script>");

            Page.ClientScript.RegisterClientScriptBlock(GetType(), "RBLScript", sb_Script.ToString(), false);
        }
    }

}

2.将CheckBoxListValidator.cs拷至C盘下编译生成dll

csc /out:C:\CheckBoxListValidator.dll /target:library C:\CheckBoxListValidator.cs

3.将CheckBoxListValidator.dll添加到工具箱,拖放至default.aspx页面

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>

<%@ Register Assembly="CheckBoxListValidator" Namespace="CheckBoxListValidator" TagPrefix="cc2" %>

<!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>无标题页</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:CheckBoxList ID="CheckBoxList1" runat="server">
        <asp:ListItem>1</asp:ListItem>
            <asp:ListItem>2</asp:ListItem>
            <asp:ListItem>3</asp:ListItem>
            <asp:ListItem>4</asp:ListItem>
            <asp:ListItem>5</asp:ListItem>
            <asp:ListItem>6</asp:ListItem>
            <asp:ListItem>7</asp:ListItem>
        </asp:CheckBoxList>
        <cc2:CheckBoxListValidator ControlToValidate="CheckBoxList1"
            ID="CheckBoxListValidator1" runat="server">必选项</cc2:CheckBoxListValidator>
        <asp:Button ID="Button1" runat="server" Text="Button" /></div>
    </form>
</body>
</html>

附：编译好的DLL下载点击下载