DevExtreme Angular - Time Zone Support

Appointments are displayed in the client time zone. The time-zone offset specified in the startDate or endDate is also taken into account (if there is any). You can force a time zone for an individual appointment via its startDateTimeZone and endDateTimeZone fields or for all appointments in the widget via its timeZone option. timeZone takes precedence over start/endDateTimeZone.

You can use the following formula to calculate an appointment's resulting time-zone offset:

`resultingOffset` = `timeZoneOffset` - `clientOffset` (or `embeddedOffset` if there is any)

where

  • timeZoneOffset is the offset of the timeZone or start/endDateTimeZone.
  • clientOffset is the offset of the client side.
  • embeddedOffset is the offset specified in the start/endDate.

The calculated offset is then added to the date-time value.

For example, if the timeZone is "Europe/Berlin" (UTC offset +1), and the client is in Tokyo (UTC offset +9), the calculated offset is 1 - 9 = -8. The time of all appointments is shifted back 8 hours: the appointment that started at 2019-01-01T12:00:00 starts at 2019-01-01T04:00:00. The same applies when the time-zone offset is specified in the date-time value (2019-01-01T12:00:00+09:00), except that this offset is used instead of the client offset.

Add the following code to allow users to change an appointment's time zone:

jQuery
JavaScript
$(function() {
    $("#schedulerContainer").dxScheduler({
        // ...
        onAppointmentFormOpening: function(e) {
            e.form.itemOption("startDateTimeZone", { visible: true });
            e.form.itemOption("endDateTimeZone", { visible: true });
        }
    });
})
Angular
app.component.html
app.component.ts
app.module.ts
<dx-scheduler ...
    (onAppointmentFormOpening)="showTimeZoneFields($event)">
</dx-scheduler>
import { Component } from '@angular/core';

@Component({
    selector: 'app-root',
    templateUrl: './app.component.html',
    styleUrls: ['./app.component.css']
})
export class AppComponent {
    showTimeZoneFields(e) {
        e.form.itemOption("startDateTimeZone", { visible: true });
        e.form.itemOption("endDateTimeZone", { visible: true });
    }
}
import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { AppComponent } from './app.component';

import { DxSchedulerModule } from 'devextreme-angular';

@NgModule({
    declarations: [
        AppComponent
    ],
    imports: [
        BrowserModule,
        DxSchedulerModule
    ],
    providers: [],
    bootstrap: [AppComponent]
})
export class AppModule { }
Vue
App.vue
<template> 
    <dx-scheduler ...
        @appointment-form-opening="showTimeZoneFields"
    />
</template>
<script>
import 'devextreme/dist/css/dx.common.css';
import 'devextreme/dist/css/dx.light.css';

import DxScheduler from 'devextreme-vue/scheduler';

export default {
    components: {
        DxScheduler
    },
    data() {
        return { /* ... */ }
    },
    methods: {
        showTimeZoneFields: (e) => {
            e.form.itemOption("startDateTimeZone", { visible: true });
            e.form.itemOption("endDateTimeZone", { visible: true });
        }
    }
}
</script>
React
App.js
import React from 'react';

import 'devextreme/dist/css/dx.common.css';
import 'devextreme/dist/css/dx.light.css';

import Scheduler from 'devextreme-react/scheduler';

class App extends React.Component {
    render() {
        return (
            <Scheduler ...
                onAppointmentFormOpening={this.showTimeZoneFields}
            />
        );
    }
    showTimeZoneFields(e) {
        e.form.itemOption("startDateTimeZone", { visible: true });
        e.form.itemOption("endDateTimeZone", { visible: true });
    }
}
export default App;

To allow a user to change the widget's time zone, implement a select box as shown in the Time Zone Support demo.