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Telerik Validation Message for Blazor

Updated on Oct 1, 2026

The Telerik Validation Message for Blazor adds built-in styling and customization options on top of the standard .NET ValidationMessage, such as Template and Class parameters.

Basics

To use a Telerik Validation Message:

Add the <TelerikValidationMessage> tag.

Set the For parameter in the same way as with a standard Blazor <ValidationMessage>. There are two options:

If the TelerikValidationMessage is in the same component as the Form or if the Form model object is available, use a lambda expression that points to a property of the Form model.

RAZOR

<TelerikValidationMessage For="@(() => Customer.FirstName)" />

@code {
    private CustomerModel Customer { get; set; } = new();

    public class CustomerModel
    {
        public string FirstName { get; set; } = string.Empty;
    }
}

If the validation message is in a child component that receives a ValueExpression, set the For parameter directly to the expression, without a lambda.

RAZOR

<TelerikValidationMessage For="@FirstNameExpression" />

@code {
    [Parameter]
    public Expression<System.Func<string>>? FirstNameExpression { get; set; }
}

Refer to the following sections for additional information and examples with the Telerik Form and standard Blazor <EditForm>.

Using with TelerikForm

The Telerik Form displays inline validation messages by default if validation is enabled. You may need to define <TelerikValidationMessage> components manually when you want to:

Use form item templates. In this case, add the validation message in the form item template.
Customize the validation messages, for example, change their rendering with a validation message template. In this case, add the validation message inside a Form item template.
Customize the placement of the validation messages in the Form, so that they are outside the Form item containers. In this case, consider a <FormItemsTemplate> that gives you full control over the Form rendering between the form items. Alternatively, consider a Telerik ValidationSummary.

Use Telerik ValidationMessage in a TelerikForm

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Using with EditForm

In an existing Blazor EditForm, replace the <ValidationMessage> tags with <TelerikValidationMessage> tags. The For parameter is set in the same way for both validation components.

Use Telerik ValidationMessage in an EditForm

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The Telerik ValidationMessage allows you to customize its rendering with a nested <Template> tag. The template context is an IEnumerable<string> collection of all messages for the validated model property.

Using ValidationMessage Template

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Class

Use the Class parameter of the Validation Message to add a custom CSS class to the span.k-form-error. This element holds the validation message.

Using TelerikValidationMessage Class

RAZOR

<TelerikValidationMessage Class="bold-blue"
                          For="@(() => Employee.FirstName)" />

<style>
    .bold-blue {
        font-weight: bold;
        color: blue;
    }
</style>

Next Steps

Explore TelerikValidationTooltip