ASP.NET8 using DataTables.net – Part3 – State saving

• Download source

1 ASP.NET8 using jQuery DataTables.net

I was evaluating the jQuery DataTables.net component [1] for usage in ASP.NET8 projects and created several prototype (proof-of-concept) applications that are presented in these articles.

1.1 Articles in this series

Articles in this series are:

• ASP.NET8 using DataTables.net – Part1 – Foundation
• ASP.NET8 using DataTables.net – Part2 – Action buttons
• ASP.NET8 using DataTables.net – Part3 – State saving
• ASP.NET8 using DataTables.net – Part4 – Multilingual
• ASP.NET8 using DataTables.net – Part5 – Passing additional parameters in AJAX
• ASP.NET8 using DataTables.net – Part6 – Returning additional parameters in AJAX
• ASP.NET8 using DataTables.net – Part7 – Buttons regular
• ASP.NET8 using DataTables.net – Part8 – Select rows
• ASP.NET8 using DataTables.net – Part9 – Advanced Filters

2 Final result

The goal of this article is to create a proof-of-concept application that demos DataTables.net component state saving. Let us present the result of this article. Here on this screen, you see the example app in a certain “state”, that is filter “mark” is applied, and sort is done by “Family name” descending.

Users often ask that when they navigate away from the page and then return, they are in the same state they left. That is shown in this article, you can in this application navigate away and come back, and the DataTables component will be in the same state as when you left.

The topic of this article is to show how to implement it. It is quite easy, that is a feature included in the component, and the state is saved on the client side, inside browser storage.

3 Client-side DataTables.net component

Here I will just show what the ASP.NET view using DataTables component looks like.

<!-- Employees.cshtml -->
<partial name="_LoadingDatatablesJsAndCss" />

@{
    <div class="text-center">
        <h3 class="display-4">Employees table</h3>
    </div>

    <!-- Here is our table HTML element defined. JavaScript library Datatables
    will do all the magic to turn it into interactive component -->
    <table id="EmployeesTable01" class="table table-striped table-bordered ">
    </table>

}


<script>
    // Datatables script initialization=========================================
    // we used defer attribute on jQuery so it might not be available at this point
    // so we go for vanilla JS event

    document.addEventListener("DOMContentLoaded", InitializeDatatable);

    function InitializeDatatable() {
        $("#EmployeesTable01").dataTable({
            //processing-Feature control the processing indicator.
            processing: true,
            //paging-Enable or disable table pagination.
            paging: true,
            //info-Feature control table information display field
            info: true,
            //ordering-Feature control ordering (sorting) abilities in DataTables.
            ordering: true,
            //searching-Feature control search (filtering) abilities
            searching: true,
            //search.return-Enable / disable DataTables' search on return.
            search: {
                return: true
            },
            //autoWidth-Feature control DataTables' smart column width handling.
            autoWidth: true,
            //lengthMenu-Change the options in the page length select list.
            lengthMenu: [10, 15, 25, 50, 100],
            //pageLength-Change the initial page length (number of rows per page)
            pageLength: 10,

            //order-Initial order (sort) to apply to the table.
            order: [[1, 'asc']],

            //serverSide-Feature control DataTables' server-side processing mode.
            serverSide: true,

            //stateSave-State saving - restore table state on page reload.
            stateSave: true,
            //stateDuration-Saved state validity duration.
            //-1 sessionStorage will be used, while for 0 or greater localStorage will be used.
            stateDuration: -1,

            //Load data for the table's content from an Ajax source.
            ajax: {
                "url": "@Url.Action("EmployeesDT", "Home")",
                "type": "POST",
                "datatype": "json"
            },

            //Set column specific initialisation properties
            columns: [
                //name-Set a descriptive name for a column
                //data-Set the data source for the column from the rows data object / array
                //title-Set the column title
                //orderable-Enable or disable ordering on this column
                //searchable-Enable or disable search on the data in this column
                //type-Set the column type - used for filtering and sorting string processing
                //visible-Enable or disable the display of this column.
                //width-Column width assignment.
                //render-Render (process) the data for use in the table.
                //className-Class to assign to each cell in the column.

                {   //0
                    name: 'id',
                    data: 'id',
                    title: "Employee Id",
                    orderable: true,
                    searchable: false,
                    type: 'num',
                    visible: true
                },
                {
                    //1
                    name: 'givenName',
                    data: "givenName",
                    title: "Given Name",
                    orderable: true,
                    searchable: true,
                    type: 'string',
                    visible: true
                },
                {
                    //2
                    name: 'familyName',
                    data: "familyName",
                    title: "Family Name",
                    orderable: true,
                    searchable: true,
                    type: 'string',
                    visible: true
                },
                {
                    //3
                    name: 'town',
                    data: "town",
                    title: "Town",
                    orderable: true,
                    searchable: true,
                    type: 'string',
                    visible: true
                },
                {
                    //4
                    name: 'country',
                    data: "country",
                    title: "Country",
                    orderable: true,
                    searchable: true,
                    type: 'string',
                    visible: true
                },
                {
                    //5
                    name: 'email',
                    data: "email",
                    title: "Email",
                    orderable: true,
                    searchable: true,
                    type: 'string',
                    visible: true,
                    width: "150px",
                    className: 'text-center '
                },
                {
                    //6
                    name: 'phoneNo',
                    data: "phoneNo",
                    title: "Phone Number",
                    orderable: false,
                    searchable: true,
                    type: 'string',
                    visible: true
                },
                {
                    //7
                    name: 'actions',
                    data: "actions",
                    title: "Actions",
                    orderable: false,
                    searchable: false,
                    type: 'string',
                    visible: true,
                    render: renderActions
                },
                {
                    //8
                    name: 'urlForEdit',
                    data: "urlForEdit",
                    title: "urlForEdit",
                    orderable: false,
                    searchable: false,
                    type: 'string',
                    visible: false
                }
            ]
        });

        function renderActions(data, type, row, meta) {
            //for Edit button we get Url from the table data
            let html1 =
                '<a class="btn btn-info" href="' +
                row.urlForEdit + '">Edit</a>';

            //for Info button we create Url in JavaScript
            let infoUrl = "@Url.Action("EmployeeInfo", "Home")" +
                "?EmployeeId=" + row.id;
            let html2 =
                '<a class="btn btn-info"  style="margin-left: 10px" href="' +
                infoUrl + '">Info</a>';

            return html1 + html2;
        }
    }
</script>

Note properties “stateSave” and “stateDuration” in the configuration of DataTables component. They just need to be activated to use that functionality.

• Property stateSave - State saving - restore table state on page reload.
• Property stateDuration - Saved state validity duration. If set to -1 sessionStorage will be used, while for 0 or greater localStorage will be used.

More about these properties can be found in the manual at [1]. The application here is just a proof of concept for ASP.NET environment.

4 How Save State works

It is always interesting to see how things work from the inside. With Chrome DevTools we can have a peek into browser Session storage.

You can see that the DataTables.net component has created a key for itself, for that particular URL, since there can be several pages with DataTables.net component and each needs to preserve its own state. You can see that the state is saved in a big JSON, and there are our search phrase “mark” and “order by column 2, descending” setting.

5 Conclusion

The full example code project can be downloaded.

6 References

[1] https://datatables.net/