Question

我需要在c＃asp net中限制用户在GridView上选择的复选框的数量。

我尝试了下面的代码，但我有两个问题：

警告弹出 'Cannot check more than 3 check boxes' 后，始终会选中复选框号码4;
启用按钮 btn 并验证表单。

我错过了什么？

这段代码出了什么问题？

提前谢谢。

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

<!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></title>
    <script type="text/javascript">
        function CheckCheck() {
            var chkBoxList = document.getElementById('<%=GridView1.ClientID %>');
            var chkBoxCount = chkBoxList.getElementsByTagName("input");

            var btn = document.getElementById('<%=btn.ClientID %>');
            var i = 0;
            var tot = 0;
            for (i = 0; i < chkBoxCount.length; i++) {
                if (chkBoxCount[i].checked) {
                    tot = tot + 1;
                }
            }

            if (tot > 3) {
                alert('Cannot check more than 3 check boxes');
            }
        }

    </script>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false">
            <Columns>
                <asp:TemplateField>
                    <ItemTemplate>
                        <asp:CheckBox ID="cbSelProduct" runat="server" onclick="javascript:CheckCheck();" />
                        <asp:HiddenField ID="HiddenField1" runat="server" Value='<%#Eval("name")%>' />
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:BoundField ItemStyle-Width="250px" DataField="name" HeaderText="name" />
            </Columns>
        </asp:GridView>
        <asp:Button runat="server" ID="btn" Text="Send" OnClick="btn_Click" />
    </div>
    </form>
</body>
</html>

Answer 1

您需要取消选中第4个已选中的复选框：

function CheckCheck()
{
    var chkBoxList = document.getElementById('<%=GridView1.ClientID %>');
    var chkBoxCount = chkBoxList.getElementsByTagName("input");

    var btn = document.getElementById('<%=btn.ClientID %>');
    var i = 0;
    var tot = 0;
    for (i = 0; i < chkBoxCount.length; i++)
    {
        if (chkBoxCount[i].checked)
        {
            tot = tot + 1;

            if (tot > 3)
            {
                alert('Cannot check more than 3 check boxes');
                chkBoxCount[i].checked = false;
                return;
            }
        }
    }
}

限制在c＃中gridview中选中的复选框数量

1 个答案: