React Form - Handle the Value Change Event

To process a new form item value, you need to handle the fieldDataChanged event. If the handling function is not going to be changed during the lifetime of the UI component, assign it to the onFieldDataChanged property when you configure the UI component.

jQuery
JavaScript
$(function() {
    $("#formContainer").dxForm({
        onFieldDataChanged: function (e) {
            var updatedField = e.dataField;
            var newValue = e.value;
            // Event handling commands go here
        }
    });
});
Angular
HTML
TypeScript
<dx-form ...
    (onFieldDataChanged)="form_fieldDataChanged($event)">
</dx-form>
import { DxFormModule } from "devextreme-angular";
// ...
export class AppComponent {
    // ...
    form_fieldDataChanged (e) {
        let updatedField = e.dataField;
        let newValue = e.value;
        // Event handling commands go here
    }
}
@NgModule({
    imports: [
        // ...
        DxFormModule
    ],
    // ...
})
Vue
App.vue
<template>
    <DxForm @field-data-changed="formFieldDataChanged">
        <!-- ... -->
    </DxForm>
</template>
<script>
import 'devextreme/dist/css/dx.light.css';

import { DxForm } from 'devextreme-vue/form';

export default {
    components: {
        DxForm
    },
    data() {
        return {
            // ...
        };
    },
    methods: {
        formFieldDataChanged(e) {
            const updatedField = e.dataField;
            const newValue = e.value;
            // Event handling commands go here
        }
    }
};
</script>
React
App.js
import React from 'react';

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

import { Form } from 'devextreme-react/form';

class App extends React.Component {
    constructor() {
        super();
        this.formFieldDataChanged = this.formFieldDataChanged.bind(this);
    }

    render() {
        return (
            <Form onFieldDataChanged={this.formFieldDataChanged}>
                {/* ... */}
            </Form>
        );
    }

    formFieldDataChanged(e) {
        const updatedField = e.dataField;
        const newValue = e.value;
        // Event handling commands go here
    }
}

export default App;
jQuery

If you are going to change event handlers at runtime, or if you need to attach several handlers to the fieldDataChanged event, subscribe to this event using the on(eventName, eventHandler) method.

JavaScript
var fieldDataChangedHandler1 = function (e) {
    var updatedField = e.dataField;
    var newValue = e.value;
    // First handler of the "fieldDataChanged" event
};

var fieldDataChangedHandler2 = function (e) {
    var updatedField = e.dataField;
    var newValue = e.value;
    // Second handler of the "fieldDataChanged" event
};

$("#formContainer").dxForm("instance")
    .on("fieldDataChanged", fieldDataChangedHandler1)
    .on("fieldDataChanged", fieldDataChangedHandler2);
See Also
jQuery
Angular
Vue
React