Custom Validator

Does not start with 'A'.

ClientValidationFunction & IsValid

The ClientValidationFunction property is accepted for migration compatibility. In Web Forms it referenced a client-side JavaScript function — Blazor does not execute client scripts, so this is a migration stub. IsValid indicates whether the control passes validation.

Validation failed.

Code:

<CustomValidator ServerValidate="@DoesItStartWithA" ControlRef="@Name" Text="Does not start with 'A'." />

<!-- Migration compatibility properties -->
<CustomValidator ServerValidate="@AlwaysValid"
                 ControlRef="@ClientValRef"
                 ClientValidationFunction="CheckValue"
                 IsValid="true"
                 Text="Validation failed." />