React Validator - CustomRule
The validation logic should be implemented within the validationCallback function. See this topic for details on using the custom rule for the server-side validation.
message
You do not have to specify this field. In this instance, a default message will be shown. To include the name of the validated editor into the default validation message as a subject, set the name field of the dxValidator object.
If you assign an empty string to the message field, the message will not be shown.
reevaluate
Indicates whether the rule should be always checked for the target value or only when the target value changes.
type
Set this field to "custom" to define a rule that will be broken as a result of custom validation performed by the validationCallback function.
validationCallback
Name | Type | Description |
---|---|---|
value | | |
The validated value. |
rule |
The current rule object that exposes user-defined options, the isValid and message fields, and the rule type-specific fields. |
|
validator |
The Validator object that initiated the validation. |
|
data |
The current row data. Exists only when you validate a DataGrid or TreeList cell's value. |
In the following code, only odd numbers are considered valid:
jQuery
$(function () { $("#numberBoxContainer").dxNumberBox({ value: 3 }).dxValidator({ validationRules: [{ type: "custom", validationCallback: validationCallback, message: "This is an even number. Enter an odd one." }] }); }); function validationCallback (e) { return e.value % 2 == 0; }
Angular
<dx-number-box [value]="3"> <dx-validator> <dxi-validation-rule type="custom" [validationCallback]="validationCallback" message="This is an even number. Enter an odd one."> </dxi-validation-rule> </dx-validator> </dx-number-box>
import { DxNumberBoxModule, DxValidatorModule } from "devextreme-angular"; // ... export class AppComponent { validationCallback (e) { return e.value % 2 == 0; } } @NgModule({ imports: [ DxNumberBoxModule, DxValidatorModule, // ... ], // ... })
See this topic for a server-side validation example.
If you have technical questions, please create a support ticket in the DevExpress Support Center.