CompareValidator component

This article demonstrates how to use RadzenCompareValidator.

Basic usage

RadzenCompareValidator compares the user input agains a predefined value or another component.

To use it perform these steps:

1. Add an input component and set its Name. Data-bind its value to a model property via @bind-Value=@model.Property.
2. Add RadzenCompareValidator and set its Component property to the Name of the input component. Set its Value property to the value you want to compare with (usually another model property).

Important

RadzenCompareValidator works only inside RadzenTemplateForm.

Here is a typical user registration form which checks if the user entered the same password.

<RadzenTemplateForm TItem="Registration" Data=@model>
    <p>
      <RadzenLabel Text="Password" />
      <RadzenPassword Name="Password" @bind-Value=@model.Password />
      <RadzenRequiredValidator Component="Password" Text="Enter password" />
    </p>
    <p>
        <RadzenLabel Text="Repeat Password" />
        <RadzenPassword Name="RepeatPassword" @bind-Value=@model.RepeatPassword />
        <RadzenRequiredValidator Component="RepeatPassword" Text="Repeat your password" />
        <RadzenCompareValidator Visible=@(!string.IsNullOrEmpty(model.RepeatPassword)) Value=@model.Password Component="RepeatPassword" Text="Passwords should be the same" Popup=@popup Style="position: absolute" />
    </p>
    <RadzenButton ButtonType="ButtonType.Submit" Text="Submit"></RadzenButton>
</RadzenTemplateForm>
@code {
    class Registration
    {
        public string Password { get; set; }
        public string RepeatPassword { get; set; }
    }

    Registration model = new Registration();
}

Conditional validation

To make the validator conditional you can set its Visible property. When set to false the validator will not run. In this example Visible is set to !string.IsNullOrEmpty(model.RepeatPassword) - the validator will not run if RepeatPassword is empty.

<RadzenCompareValidator Visible=@(!string.IsNullOrEmpty(model.RepeatPassword)) Value=@model.Password Component="RepeatPassword" Text="Passwords should be the same" Popup=@popup Style="position: absolute" />

Comparison operator

By default RadzenCompareValidator checks if the component value is equal to Value. This can be changed via the Operator property.

<RadzenNumeric Name="Count" @bind-Value=@model.Count />
<RadzenCompareValidator Component="Count" Text="Count should be less than 10" Operator="CompareOperator.LessThan" Value="10" />

Appearance

By default RadzenCompareValidator appears next to the component it validates.

To make it appear below set its Style to "display:block".

<RadzenNumeric Name="Count" @bind-Value=@model.Count />
<RadzenCompareValidator Style="display:block" Component="Count" Text="Count should be less than 10" Operator="CompareOperator.LessThan" Value="10" />

To make it appear as a styled popup set its Popup property to true and set its CSS position to absolute. The validated component should have display: block so the validation message appears right below it.

<RadzenNumeric Name="Count" @bind-Value=@model.Count Style="display:block" />
<RadzenCompareValidator Style="position:absolute" Popup="true" Component="Count" Text="Count should be less than 10" Operator="CompareOperator.LessThan" Value="10" />