让用户在复选框列表验证中选择至少一个复选框

Question

我想在复选框列表中至少选择一个复选框进行验证。我得到错误，如'cvDaysofWeeklist'的ControlToValidate属性所引用的Control'CheckBoxListDaysofWeek'无法验证。下面是我的asp代码。

<asp:CheckBoxList ID="CheckBoxListDaysofWeek" runat="server" RepeatDirection="Horizontal" CssClass="formatcheckboxlist" ValidationGroup="ReportSearch" CausesValidation="true"> 
             <asp:ListItem Text="Mon" Value="1" Selected="True"></asp:ListItem> 
             <asp:ListItem Text="Tue" Value="2" Selected="True"></asp:ListItem> 
             <asp:ListItem Text="Wed" Value="3" Selected="True"></asp:ListItem> 
             <asp:ListItem Text="Thu" Value="4" Selected="True"></asp:ListItem> 
             <asp:ListItem Text="Fri" Value="5" Selected="True"></asp:ListItem> 
             <asp:ListItem Text="Sat" Value="6"></asp:ListItem> 
             <asp:ListItem Text="Sun" Value="7"></asp:ListItem> 
            </asp:CheckBoxList> 
            <ams:AMSCustomValidator ID="cvDaysofWeeklist" runat="server" ClientValidationFunction="ValidateDaysofWeekList" ControlToValidate="CheckBoxListDaysofWeek" 
             Display="None" ValidationGroup="ReportSearch" 
             Resource="Content" ResourceName="TAGSEARCH_TEXTBOXMANUFACTURESTARTDATEVALIDATOR" /> 
             <ajaxToolkit:ValidatorCalloutExtender ID="vce_DaysofWeek" runat="server" TargetControlID="cvDaysofWeeklist" HighlightCssClass="HighlightField"></ajaxToolkit:ValidatorCalloutExtender>` 

和我的javascript功能

function ValidateDaysofWeekList(source, args) { 
     var chkListDow = document.getElementById('<%= CheckBoxListDaysofWeek.ClientID %>'); 
     var chkListinputs = chkListDow.getElementsByTagName("input"); 
     for (var i = 0; i < chkListinputs.length; i++) { 
      if (chkListinputs[i].checked) { 
       args.IsValid = true; 
       return; 
      } 
     } 
     args.IsValid = false; 
    } 

Answer 1

如果您使用的CustomValidator，你不应该设置你的CheckBoxList ControlToValidate属性。

如果将ControlToValidate设置为CheckBoxList，.NET将引发异常。