RadzenRequiredValidator Class

A validator component that ensures a form input component has a non-empty value. RadzenRequiredValidator verifies that required fields are filled before form submission. Must be placed inside a RadzenTemplateForm<T> and associated with a named input component. Checks if the associated component has a value (HasValue returns true) and that the value is not equal to the optional DefaultValue. For text inputs, an empty string is considered invalid. For dropdowns and other components, null or default values are considered invalid. The validation message can be customized via the Text property and displayed inline, as a block, or as a popup depending on the Style property.

Inheritance

Implements

Inherited Members

Syntax

public class RadzenRequiredValidator : ValidatorBase, IComponent, IHandleEvent, IHandleAfterRender, IRadzenFormValidator

Examples

Basic required field validation:

<RadzenTemplateForm TItem="Model" Data=@model>
  <RadzenTextBox style="display: block" Name="Email" @bind-Value=@model.Email />
  <RadzenRequiredValidator Component="Email" Text="Email is required" Style="position: absolute" />
</RadzenTemplateForm>
@code {
 class Model
 {
   public string Email { get; set; }
 }

 Model model = new Model();
}

Dropdown validation with default value:

<RadzenDropDown Name="Country" @bind-Value=@model.CountryId Data=@countries />
<RadzenRequiredValidator Component="Country" DefaultValue="0" Text="Please select a country" />

Constructors

public RadzenRequiredValidator()

Properties

public object DefaultValue { get; set; }

public string Text { get; set; }

Methods

protected override bool Validate(IRadzenFormComponent component)