Component Configuration Syntax

Create and Configure a Component

Any DevExtreme UI component must be placed in a container. This role is played by a <div> HTML element. Add a <div> to the <body> tag of your page. Make sure that this <div> has the id attribute specified.

HTML

<div id="buttonContainer"></div>

DevExtreme supplies a jQuery plugin for each UI component. To create, for example, the Button UI component within the buttonContainer element, use the dxButton() plugin as the following code shows.

JavaScript

$(function () {
    $("#buttonContainer").dxButton();
});

To configure a UI component, pass an object to the plugin as shown in the following code. Properties of this object mirror the properties of the UI component.

JavaScript

$(function () {
    $("#buttonContainer").dxButton({
        text: "Click me!",
        onClick: function () {
            alert("Hello world!");
        }
    });
});

Get and Set Options

All operations with UI component properties are carried out using the option() method. You can use it to do the following.

Get a Single Option

JavaScript

var dataGridInstance = $("#dataGridContainer").dxDataGrid("instance");
var dataSource = dataGridInstance.option("dataSource");
var editMode = dataGridInstance.option("editing.mode");

// ---------- or ----------
var dataSource = $("#dataGridContainer").dxDataGrid("option", "dataSource");
var editMode = $("#dataGridContainer").dxDataGrid("option", "editing.mode");

Get All Options

JavaScript

var dataGridInstance = $("#dataGridContainer").dxDataGrid("instance");
var dataGridOptions = dataGridInstance.option();

// ---------- or ----------
var dataGridOptions = $("#dataGridContainer").dxDataGrid("option");

Set a Single Option

JavaScript

var dataGridInstance = $("#dataGridContainer").dxDataGrid("instance");
dataGridInstance.option("dataSource", []);
dataGridInstance.option("editing.mode", "batch");

// ---------- or ----------
$("#dataGridContainer").dxDataGrid("option", "dataSource", []);
$("#dataGridContainer").dxDataGrid("option", "editing.mode", "batch");

NOTE

If you perform several property changes, wrap them with the beginUpdate() and endUpdate() method calls. This prevents the UI component from being unnecessarily refreshed and from events being raised. Use an object instead if you need to change several properties at once.

Set Several Options

JavaScript

var dataGridInstance = $("#dataGridContainer").dxDataGrid("instance");
dataGridInstance.option({
    dataSource: [],
    editing: {
        mode: "cell"
    }
});

// ---------- or ----------
$("#dataGridContainer").dxDataGrid({
    dataSource: [],
    editing: {
        mode: "cell"
    }
});

NOTE

When you pass an object to the option(options) method or to the jQuery plugin at runtime as shown in the previous code, properties specified in this object will be merged with the properties that were specified at design time.

This works properly unless the properties were specified as arrays. If the latter is true, set new properties between beginUpdate() and endUpdate() method calls. The following code sample demonstrates the described technique using an example of the valueAxis array in the Chart UI component:

JavaScript

var chart = $("#chartContainer").dxChart({
    // ...
    valueAxis: [{
        name: "axis1",
        // ...
    }, {
        name: "axis2",
        // ...
    }]
}).dxChart("instance");

chart.beginUpdate();
chart.option("valueAxis[0].visible", false);
chart.option("valueAxis[1].grid.visible", false);
chart.endUpdate();

Call Methods

To call a UI component method, pass its name to the jQuery plugin.

JavaScript

var allSeries = $("#chartContainer").dxChart("getAllSeries");

If a method accepts arguments, pass them right after the method's name.

JavaScript

var fruitsSeries = $("#chartContainer").dxChart("getSeriesByName", "fruits");

As an alternative, you can obtain the UI component instance first, and then call any method of this instance.

JavaScript

var chartInstance = $("#chartContainer").dxChart("instance");
var allSeries = chartInstance.getAllSeries();
var fruitsSeries = chartInstance.getSeriesByName("fruits");

Get a Widget Instance

Use the following code to get a UI component instance:

JavaScript

var chartInstance = $("#chartContainer").dxChart("instance");

If the UI component is not yet instantiated, this code throws an E0009 exception that you can handle with a try...catch block:

JavaScript

try {
    var chartInstance = $("#chartContainer").dxChart("instance");
}
catch (err) {
    alert("Exception handled: " + err.message);
}

Instead of the exception, you can get a truthy or falsy value that can be used in conditional statements. To do this, call the UI component class's static getInstance(element) method. This method returns undefined if the UI component is not instantiated for the element:

JavaScript

var element = document.getElementById("chartContainer");
var chartInstance = DevExpress.viz.dxChart.getInstance(element);
if (chartInstance) {
    // Your code goes here
}

Handle Events

Subscribe to an Event

You can subscribe to an event using a configuration property. All event handling properties are given names that begin with on.

JavaScript

$("#dataGridContainer").dxDataGrid({
    onCellClick: function (e) {
        // Handles the "cellClick" event
    },
    onSelectionChanged: function (e) {
        // Handles the "selectionChanged" event
    }
});

As a more flexible solution, you can use the on() method. It allows you to subscribe to events at runtime and attach several handlers to a single event.

JavaScript

var dataGridInstance = $("#dataGridContainer").dxDataGrid("instance");
// Subscribes to the "cellClick" and "selectionChanged" events
dataGridInstance
    .on({
        "cellClick": cellClickHandler,
        "selectionChanged": selectionChangedHandler
    });

JavaScript

var dataGridInstance = $("#dataGridContainer").dxDataGrid("instance");
// Attaches several handlers to the "cellClick" event
dataGridInstance
    .on("cellClick", cellClickHandler1)
    .on("cellClick", cellClickHandler2);

Unsubscribe from an Event

To detach a specific handler from an event, call the off(eventName, handler) method.

JavaScript

var dataGridInstance = $("#dataGridContainer").dxDataGrid("instance");
// Detaches the "cellClickHandler1" from the "cellClick" event leaving other handlers (if any) intact
dataGridInstance.off("cellClick", cellClickHandler1)

You can also use this method to detach all handlers from a particular event.

JavaScript

var dataGridInstance = $("#dataGridContainer").dxDataGrid("instance");
// Detaches all handlers from the "cellClick" event
dataGridInstance.off("cellClick")

If you subscribed to an event using an onEventName property, you can unsubscribe from it by setting this property to undefined.

JavaScript

var dataGridInstance = $("#dataGridContainer").dxDataGrid("instance");
dataGridInstance.option("onCellClick", undefined);

Dispose of a Widget

To dispose of a DevExtreme UI component, free up the allocated resources by calling the dispose() method. Then, remove the UI component's associated DOM node:

JavaScript

$("#dataGridContainer").dxDataGrid("dispose");
$("#dataGridContainer").remove();

Component Configuration Syntax

Create and Configure a Component

See Also

Get and Set Options

Get a Single Option

Get All Options

Set a Single Option

Set Several Options

Call Methods

See Also

Get a Widget Instance

Handle Events

Subscribe to an Event

Unsubscribe from an Event

See Also

Dispose of a Widget