Select/Un-Select All checkboxes in Gridview Header & Vice Versa

Introduction

This has become a common task to implement select/un-select all child check boxes via a parent check box (in Header) and vice versa. This post is basically describing these common tasks in a precise way along with other related sub tasks.

Background

Yesterday, I was assigned a task to add check boxes in a column of Data Grid for selection of concerned records/rows and further requirement was as below.

• All child checkboxes will be checked/un-checked using a Parent checkbox (in Header).
• Automatically check “parent checkbox” based on all child boxes checked/unchecked.

Further during the implementation, I faced a validation requirement of “Select at least one checkbox” before proceeding. So I have combined all these three(3) tasks in this post to help other users in future.

First of all, I will start with the HTML content (aspx page). Let’s have a look below.

Using the Code

HTML Content (.ASPX Page)

<asp:TemplateColumn>
   <HeaderTemplate>
        <input id="chkAll" class="cbAll"
        onclick="javascript:SelectAllCheckboxes1(this);"
        runat="server" type="checkbox" />
  </HeaderTemplate>
        <ItemTemplate>
            <asp:CheckBox ID="rptCB" runat="server"
            CssClass="cbChild" /><br />
            </ItemTemplate>
</asp:TemplateColumn>

Above, I have placed a Template column in Data Grid's content, which contains two templates inside.

Header Template: which contains the "Select All" checkbox and by clicking on that, all the child check boxes will be checked or unchecked.

Item Template: which contains the child checkbox which will be shown repeatedly in the Data Grid's column and if all child boxes of Grid will be checked/un-checked, then it will result in Selection/un-selection of "Select All" checkbox , which will be present in Grid's header.

As you can see, there is a JavaScript function being called on the Parent checkbox in the header template. So my next paragraph will be describing it and its functionality.

Select/un-Select All Child Check Boxes (JavaScript)

function SelectAllCheckboxes1(chk) {

     $('#<%=MyGrid.ClientID%>').find("input:checkbox").each(function () {
         if (this != chk) {
             this.checked = chk.checked;
          }
                 });
 }

The above function will iterate the Data Grid using Jquery .each method and will select/un-select all the child checkboxes. The above function will be placed inside the script tag at the end of form tag and just before the body tag's ending.

For Task two, i.e., selection of Parent check box (Select All), in case all child checkboxes have been checked one by one, the following piece of code will be used.

Select/Un-Selected Parent Check Box (JavaScript)

$(".cbChild").change(function () {
                 var all = $('.cbChild');
                 if (all.length === all.find(':checked').length) {
                     $(".cbAll").attr("checked", true);
                 } else {
                     $(".cbAll").attr("checked", false);
                 }
             });

The above function will get all the childboxes using its class attribute and based on the scenario will select or un-select the parent check box. This function will be placed inside the script tag at the end of form tag and just before the body tag's ending.

Further for the validation, i.e Task three, we can use the following JavaScript function.

Please Select at least One Checkbox (JavaScript)

The following function can be called on the button, on which we would be performing the further processing based on selected checkbox. So, the following function will restrict the user to at least select one record.

HTML content and function both are placed below for better understanding.

function checkSelected(btn) {

           var flg;

           var gridView = document.getElementById("<%=MyGrid.ClientID %>");
           var checkBoxes = gridView.getElementsByTagName("input");
           for (var i = 0; i < checkBoxes.length; i++) {
               if (checkBoxes[i].type == "checkbox" && checkBoxes[i].checked) {
                   flg = true;
                   return;
               }
           }
           flg = false;

           if (!flg) {
               alert("Please select Record(s).");
               return false
           }

           return true;
       }

Button Content

<asp:Button ID="btnSubmit" runat="server"
    Text="Submit" onclick="Submit_Click"
    OnClientClick="return checkSelected(this);" />

Points of Interest

It's a 3 in 1 solution, which contains three mini tricks to save time. These piece of codes are client side and hence make the solution more optimized than the other available server side solutions.

At the end, I would appreciate any advice/criticism for improvement.

Hope it will help you. :)