如何将必需字段验证器添加到选中的列表框？

Question

I'm using a checked list-box inside a div tag and I want to validate the checked list-box. How can I achieve this?

Answer 1

You can use javascript to validate the checkboxlist. please find the below code to get an idea:

<script type = "text/javascript">
var minOccurance= 1
function Validate()
{
   var yourCheckboxList= document.getElementById("<%=CheckBoxList1.ClientID%>"); 
   var checkbox = yourCheckboxList.getElementsByTagName("input");
   var counter=0;
   for (var i=0;i<checkbox.length;i++)
   {
       if (checkbox[i].checked)
              counter++;
   }

   if(minOccurance>counter)
   {
       alert("Please select atleast " + minOccurance +  " item(s)");
       return false;
   }
   return true;
}
</script>

Hope this will you to solve the issue.