Data coming from an ObservableArray are displayed

Question

here is my viewModel:

ViewModel

var sitesTableModel = [
{
   nameCol: "nameCol-1",
   pagesCol: "pagesCol-1",
},
{
    nameCol: "nameCol-2",
    pagesCol: "pagesCol-2",
}];

var pagesTableModel = [
{
   lastCol: "lastCol-1",
   editedCol: "editedCol-1",
},
{
    lastCol: "lastCol-2",
    editedCol: "editedCol-2",
}];


var viewModel = {
    sitesTable: ko.observableArray(sitesTableModel),
    pagesTable: ko.observableArray(pagesTableModel),
};

then I call a webservice in this way:

AJAX Call

ajaxService = (function () {
    var ajaxGetJson = function (method, request, callback, service) {
        $.ajax({
            url: "http://localhost:2880/Whatever.svc/Method",
            type: "GET",
            data: request,
            dataType: "json",
            contentType: "application/json; charset=utf-8",
            success: function (result, statusMsg, status)
            {
                callback(result, statusMsg, status, request);
            },
            error: ServiceFailed 
        }).always(function () {
            ko.applyBindings(viewModel); 
            });
    }
    return {
        ajaxGetJson: ajaxGetJson,
    };
})();

and map the result in this way:

Mapping

function ModelTableSitesMapper(result, statusMsg, status, request) {

    var itemRow = [];

    //sitesTableModel
    result.forEach(function (entry) {
        itemRow.push({
            nameCol: entry.Title,
            pagesCol: entry.Pages,
        })
    });

    viewModel.sitesTable = ko.observableArray(itemRow);

};

And the same for the other array.

Now here is my data binding:

Data Binding

    <table id="tableDocs">  
        <tbody data-bind="foreach: documentsTable" >
        <tr>
            <td data-bind="text: nameCol">Simon Werner Hansen</td>
            <td data-bind="text: pagesCol">swh002</td>
        </tr>
        </tbody>
    </table>

and when I get the result everything is dispoayed twice in the table. I checked the model and there is no double data in the observableArray. I know Iøm declaring the object as observableArray twice, and that could be the problem but I canøt find any other way to update the array than this:

viewModel.sitesTable = ko.observableArray(itemRow);

if I do this as it should be it just does not work:

viewModel.sitesTable(itemRow);

Maybe somebody could understand there reason for this?

Answer 1

I found the problem.

I was applying the binding ko.applyBinding on the .always function of the ajax call, but because I was calling the service twice for 2 different reasons the binding was applied TWICE. That caused the duplication of data.

I just moved the binding outside the function just after I create my model.

Answer 2

What happens if you try:

var viewModel = {
    sitesTable: ko.observableArray([]),
    pagesTable: ko.observableArray([]),
};

There's no mention of what the variables you were pre-populating the arrays with are.

Then add each item to your observable directly:

function ModelTableSitesMapper(result, statusMsg, status, request) {
    //sitesTableModel
    result.forEach(function (entry) {
        viewModel.sitesTable.push({
            nameCol: entry.Title,
            pagesCol: entry.Pages,
        })
    });
};