Click here to Skip to main content
Click here to Skip to main content
Technical Blog

ASP.NET CheckBoxList Client Side Validation using JavaScript

, 24 Feb 2014 CPOL
Rate this:
Please Sign up or sign in to vote.
In this Blog, we will explore a Trick to validate whether any CheckBox inside one CheckBoxList is checked or not.
ASP.NET CheckBox Validation Nothing Checked

ASP.NET CheckBox Validation Nothing Checked

ASP.NET CheckBox Validation Atleast one Checked

ASP.NET CheckBox Validation Atleast one Checked

Introduction

In this Blog, we will explore a Trick to validate whether any CheckBox inside one CheckBoxList is checked or not.

Problem

When you define one CheckBoxList on aspx Page by writing code something like below…

<asp:CheckBoxList RepeatDirection="Horizontal" 
                  ID="chkDemo"
                  runat="server">
    <asp:ListItem Text="Apples" Value="1"></asp:ListItem>
    <asp:ListItem Text="Oranges" Value="2"></asp:ListItem>
    <asp:ListItem Text="Mangoes" Value="3"></asp:ListItem>
</asp:CheckBoxList>

It will render on Browser like below…

<table id="chkDemo">
    <tbody>
        <tr>
            <td>
                <input type="checkbox" value="1" name="chkDemo$0" id="chkDemo_0">
                <label for="chkDemo_0">Apples</label>
            </td>
            <td>
                <input type="checkbox" value="2" name="chkDemo$1" id="chkDemo_1">
                <label for="chkDemo_1">Oranges</label>
            </td>
            <td>
                <input type="checkbox" value="3" name="chkDemo$2" id="chkDemo_2">
                <label for="chkDemo_2">Mangoes</label>
            </td>
        </tr>
    </tbody>
</table>

Basically it renders number of CheckBoxes depending on the number of ListItems inside CheckBoxList.

So, what is the Logic here?

We will call one JavaScript function on a Button Click.
Button would look like…

<asp:Button runat="server" ID="Button1" Text="Submit" 
            OnClientClick="return validateCheckBoxList();" />

Inside that function, we will run the following logic to validate whether any CheckBox is checked or not.

  1. We will find the main CheckBoxList first, which is rendered as a Table.
  2. Next, we need to find all the CheckBox inside that Table.
  3. After that, we have to check if any CheckBox is checked by looping through them.
  4. If any CheckBox is checked, then break the Loop and show alert (for demo purpose).
  5. Return true if any CheckBox is checked, else show alert and return false.
function validateCheckBoxList() {
    var isAnyCheckBoxChecked = false;

    // ::: Step-1 & 2 ::: Let's get all the CheckBoxes inside the CheckBoxList.
    var checkBoxes = document.getElementById("chkDemo").getElementsByTagName("input");
    
    // ::: NOTE ::: For jsfiddle demo I have directly used the ID. 
    // Otherwise you might have to use ClientID like below...
    // document.getElementById("<%= chkDemo.ClientID %>").getElementsByTagName("input");

    // ::: Step-3 ::: Now let's Loop through the Children.
    for (var i = 0; i < checkBoxes.length; i++) {
        if (checkBoxes[i].type == "checkbox") {
            if (checkBoxes[i].checked) {
                // ::: Step-4 ::: If current CheckBox is checked, then show alert.
                // Break the Loop.
                isAnyCheckBoxChecked = true;
                alert("Atleast one CheckBox is checked");
                break;
            }
        }
    }
 
    // ::: Step-5 ::: Check if any CheckBox is checked or not.
    // Show alert and return accordingly.
    if (!isAnyCheckBoxChecked) {
        alert("No CheckBox is Checked.");
    }

    return isAnyCheckBoxChecked;
}

See the Demo

HERE.

Note

I have used the CheckBoxList ID directly, which is chkDemo. But when your ClientID changes, you can get the CheckBoxList like…

document.getElementById("<%= chkDemo.ClientID %>");

Do you find it interesting?

Share your thoughts on the Blog. Don’t forget to Like and Share.


License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Share

About the Author

Tadit Dash (ତଡିତ୍ କୁମାର ଦାଶ)
Software Developer Mindfire Solutions
India India
NOW I am a Conference Speaker. Please invite me to your College, Company, Event or Conference !!!
 
Proud Indian | Microsoft MVP | CodeProject MVP | Author | Blogger | Community Expert | Moderator | jsfiddler | Cricketer | Cook | Dancer
 
Currently working @Mindfire Solutions.
Love to code and help guys to Trap the Bug.

My Tech Blog

taditdash.wordpress.com

Programming Community Profiles

jsfiddle | Stack Overflow

Other Blog Profiles

Mindfire CRM Team Blog | Mindfire Blog

Social Profiles

Facebook | Twitter | LinkedIn | Google+

Awards

  1. Microsoft MVP 2014
  2. Code Project MVP 2014
  3. Star Achiever of the Month December 2013
  4. Mindfire Techno Idea Contest 2013 Winner
  5. Star of the Month July 2013
Follow on   Twitter   Google+   LinkedIn

Comments and Discussions

 
QuestionGood explained dude!,,, My vote for 5 ! PinmemberSujee116-Feb-14 6:22 
AnswerRe: Good explained dude!,,, My vote for 5 ! PinprotectorTadit Dash16-Feb-14 8:14 
GeneralMy vote is 5 Pinmemberjoginder-banger13-Feb-14 9:58 
GeneralRe: My vote is 5 PinprotectorTadit Dash13-Feb-14 18:30 
GeneralMy vote of 5 PinmemberCarsten V2.012-Feb-14 22:53 
GeneralRe: My vote of 5 PinmvpTadit Dash13-Feb-14 0:35 

General General    News News    Suggestion Suggestion    Question Question    Bug Bug    Answer Answer    Joke Joke    Rant Rant    Admin Admin   

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.

| Advertise | Privacy | Terms of Use | Mobile
Web04 | 2.8.141223.1 | Last Updated 24 Feb 2014
Article Copyright 2014 by Tadit Dash (ତଡିତ୍ କୁମାର ଦାଶ)
Everything else Copyright © CodeProject, 1999-2014
Layout: fixed | fluid