Questions on Kendo UI for jQuery Forum

3 answers

1.4K+ views

Prevent datasource read request to server

Hi,

How do I prevent dataSource from making request to server?
I have a costly set of data and so stored the JSON in client cache (local storage), so that even after the user navigate away from the page and back, already read data from server would be available rather than making another call to receive same data back again.

I am using local cache to store the data once read from server and want to prevent dataSource from making subsequent request when found in cache.

I tried the following, but it did not work, is there anyway to achieve this?

    var ds = new kendo.data.DataSource({
        transport: {
            read: {
                url: 'url to get data',
                dataType: "json"
            }
        },
        change: OnDataChange,
        requestStart: OnDataRequestStart
    });

function OnDataChange(e) {
    if (IsDataRequested) {
        // save it to cache
        $.jStorage.set("LargeData", e.sender.data());
        IsDataExists = true;
        IsDataRequested = false;
    }
}
 
function OnDataRequestStart(e) {
    if (IsDataExists) {
        e.preventDefault();
    }
    else {
        // Check if "key" exists in the storage
        var value = $.jStorage.get("LargeData");
        if (value) {
            IsDataExists = true;
            e.preventDefault();
            e.sender.data(value);
        }
        else {
           // Read data from server
            IsDataRequested = true;
        }
    }
}

Thanks
Muthu

Data Source

answered on 21 Sep 2012

6 answers

534 views

Using Kendo UI with MVC 4

Hello,

I'm trying to use Kendo UI with a MVC 4 app but I get the following error:

Object doesn't support property or method 'on'

I've tried including the jquery.min.js that comes with Kendo but it still does not work. MVC uses jQuery v 1.6.2 by default. I've also tried removing the 1.6.2 reference and using the 1.7.1 (aka jquery.min.js that comes with Kendo), but that too causes other code to fail. Any suggestions would be appreciated.

- Rashad

Window

answered on 21 Sep 2012

0 answers

177 views

dataSource filter, then return data deeper in object

I have an object with data I that I want to use to fill a list. When someone clicks a link it triggers the javascript below and the value from e.view.params.street_id is taken (for example: 2) and filters the obj's street_id field. I then want to take data from the filtered objects in the "addresses" parameter, and fill #template (below) with the data from that. Can I do that? and how?

<script id="template" type="text/x-kendo-template">

<span>${street_number}</span>
<span>${notes}</span>

</script>

var obj = [

{

"street_id": "1",

"street_name": "First St",

"addresses": [

{

"street_number": "100",

"notes": "Example notes..."

},

{

"street_number": "101",

"notes": ""

}

]

},

{

"street_id": "2",

"street_name": "Second St",

"addresses": [

{

"street_number": "200",

"notes": ""

},

{

"street_number": "201",

"notes": "Test notes..."

}

]

}

];

var template = kendo.template($('#template').html());

var dataSource = new kendo.data.DataSource({

data: obj,

filter: {

field: 'street_id',

operator: 'eq',

value: e.view.params.street_id

},

change: function() {

$('#streets').html(kendo.render(template, this.view()));

}

});

dataSource.read();

Data Source

asked on 20 Sep 2012

4 answers

295 views

Combobox drop panel/dropdown stuck on IE 8

With reference to the attached image

Following is the behavior:

Issue happens only on the first drop panel that is clicked, once its open it doesn't close, all the other combos work except the first one that is clicked.
Issue does not happen when there is more content on the page, basically page height is large enough.

We are using Select tag and convert it to combobox

$(this).kendoComboBox({

filter: "contains",

height: 200,

change: function (e) {

if (this._selected == null) {

this.text("(None)");

}

});

We are using:
jQuery v1.7.1
Kendo UI v2011.3.1129
ASP.Net MVC 3 (not sure if that matters)

ComboBox

answered on 20 Sep 2012

0 answers

342 views

How to debug mvvm clientside?

As an example the below code is using a kendo observable with a remote datasource model and view. I understand how to debug the ajax call to retrieve the data. But where and how do I verify that the data matches the model, then when I bind my form to my viewModel where do I debug this is for example the dropdownbox is not filling with data even though the ajax data request was a success and see the ajax response in the debugger. But can't tell where my error is??

<!DOCTYPE html>

<html>

<head>

<title></title>

<script src="js/lib/jquery/jquery-1.8.1.min.js"></script>

<script src="js/lib/kendoui/kendo.web.min.js"></script>

<link href="css/KendoUI/kendo.common.css" rel="stylesheet" />

<link href="css/KendoUI/kendo.blueopal.css" rel="stylesheet" />

</head>

<body>

<div id="example" class="k-content">

<div id="form-container">

<div class="demo-section">

Select Product: <select data-role="dropdownlist" data-option-label="Select product"

data-value-field="ID" data-text-field="lastName"

data-bind="source: productsSource, value: selectedProduct"></select>

<button data-bind="click: save, enabled: hasChanges" class="k-button">Submit All Changes</button>

</div>

<div class="demo-section product-info"></div>

<ul>

<li><label>ID</label> <span data-bind="text:selectedProduct.ID, events: { change: change }"></span></li>

<li><label>Last Name</label> <input type="text" class="k-textbox" id="lname" data-bind="value: selectedProduct.lastName, events: { change: change }" /></li>

</ul>

<button data-bind="click: remove" class="k-button">Delete Product</button>

</div>

<script>

var crudServiceBaseUrl = "http://127.0.0.1:8081/cors";

var viewModel = kendo.observable({

productsSource: new kendo.data.DataSource({

transport : {

read: function(operation) {

//alert("begin read")

$.ajax({

url: crudServiceBaseUrl + "/People",

dataType: "json",

success: function(response) {

// debugger;

//alert(response)

alert("success read"); //mark the operation as successful

},

error: function(e){

alert("error")

}

});

},

batch: true,

schema: {

data : "__ENTITIES",

model : {

id : "ID",

fields : {

__KEY : {

editable : false,

nullable : true

},

__STAMP : {

editable : false,

nullable : true

},

ID : {

editable : false,

nullable : true

},

firstName : {

validation : {

required : true

}

},

lastName : {

validation : {

required : true

}

}),

selectedProduct: null,

hasChanges: false,

save: function() {

this.productsSource.sync();

this.set("hasChanges", false);

},

remove: function() {

if (confirm("Are you sure you want to delete this product?")) {

this.productsSource.remove("1");

// this.set("selectedProduct", this.productsSource.view()[0]);

this.change();

}

},

// showForm: function() {

// return this.get("selectedProduct") !== null;

// },

change: function() {

this.set("hasChanges", true);

}

});

alert("bind")

kendo.bind($("#form-container"), viewModel);

</script>

</body>

</html>

MVVM

asked on 20 Sep 2012

0 answers

170 views

Problem binding chart dataSource in template

I'm trying to bind a chart using MVVM, but get this error: "Uncaught Error: The dataSource binding is not supported by the Chart widget"

Here is my template:
<script id="chart-template" type="script/x-kendo-template">
<div data-role="chart" data-series-field="value" data-categoryaxis-field="category" data-seriesdefaults-type="column" data-bind="dataSource: #: parent().parent().dataSource #" class="chart"></div>
</script>

I'm using parent to get back to the chart array's main object, since it has the datasource. If it would have worked, I would have switched that to a function that would return a new datasource specific to each chart. Is my template totally wrong, or can you really just not bind a chart's dataSource with templates yet? I'm a Kendo newbie, so I could easily be messing this up. Thanks!

Edit:
Ok, so now I got this when trying to declaratively bind the tabstrip's activate event: "Error: The activate binding is not supported by the TabStrip widget". This whole declarative initialization really seems half-baked. Can someone please comment on this? If this is the case, can you at least indicate in the documentation whether each property/event can be declaratively databound?

Charts

asked on 20 Sep 2012

0 answers

113 views

Binding to backgroundImage broken in ie8

On the html:

data-bind="style: {backgroundImage: imgSrc}"

On the observable:

imgSrc: function() { return 'url(' + this.get('filename') + ')'; }

In IE8:

this.element.style[a]=this.bindings.style[a].get() throws "Invalid argument."

this.bindings.style[a].get:

function(){
var a=this,b=a.source,c,d=a.path,f=b;
a.start();
if(a.observable) {
f=b.get(d);
while(f===undefined&&b)
b=b.parent(),b instanceof e&&(f=b.get(d));
typeof f=="function"&&(c=d.lastIndexOf("."),c>0&&(b=b.get(d.substring(0,c))),f=k(f,b),f=f(a.source)),b&&b

MVVM

asked on 20 Sep 2012

1 answer

235 views

Kendo MVVM and SPA - slow

I created my whole page as an SPA, all the links do Ajax calls and just refresh content areas. I have serious performance Issues with content areas that have Kendo widgets. With a lot of subsequent calls the app becomes slower and slower until it freezes. I checked whats happening and I see Kendo with each initalization adds <div> items to the bottom of the <body>, when my app changes the content area which is inside the body these divs stay and with each click they keep growing until they turn into a monster that kills the performance.

Is there some generic method to clean these up?

MVVM

answered on 20 Sep 2012

2 answers

181 views

[Solved] Binding and external View

Hi,

i got a external view - linked with <a href="page2.html"> from my main page. In this view is a tag which i want to bind a variable. How do i know when the view is loaded, so i can bind my variable?

Bye

Georg

MVVM

answered on 20 Sep 2012

1 answer

228 views

Datasource vs Mvvm

Trying to wrap my head around the different data access methods. I have read all the docs on datasouce and mvvm but still am a little confused. I know mvvm is a pattern but its not just code seperation as in the examples mvvm is used for dataaccess without using a datasource.

Are datasource and mvvm two different approaches to working with data?
So you could use a datasource and templating for method 1
or Mvvm for method 2

I have read a forum where someone asked about using a datasource with mvvm why would you want to?

A datasource contains part of mvvm because it has the model as part of itself.

Just trying to pick one method for development and stick with it but not sure which one to go with.

Also in Mvvm you have all the different binding methods that are a bit confusing such as html element binding or attribute binding are these to different approaches where you just need to pick either html or attribute?

Thanks,

Dan

Data Source

answered on 20 Sep 2012