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RadioButton

in namespace DotVVM.Framework.Controls

Renders a HTML radio button.

Usage & Scenarios

This control renders HTML radio button.

Use the GroupName property to define radio button groups (only one radio button in each group can be checked). Please note that the all radio buttons in the same group must be bound to the same property in the viewmodel.

Sample 1: Basic RadioButtons

The RadioButton control has the Checked property of boolean which indicates whether the control is checked or not.

Optionally, you can use the Text property to specify the label for the radio button. Or you can put the label contents inside the dot:RadioButton element.

<dot:RadioButton Checked="{value: IsCompany}" CheckedValue="{value: false}"
                 GroupName="RadioGroup">
  <img src="~/images/person.png" /> person
</dot:RadioButton>

<dot:RadioButton Checked="{value: IsCompany}" CheckedValue="{value: true}"
                 GroupName="RadioGroup" Text="company" />

<p>Is company: {{value: IsCompany}}</p>
using System.Collections.Generic;

namespace DotvvmWeb.Views.Docs.Controls.builtin.RadioButton.sample1
{
    public class ViewModel
    {
        public bool IsCompany { get; set; }
    }
}

Sample 2: Multiple RadioButtons

The RadioButton has also a property CheckedItem which point to a property in the viewmodel. This is an alternative to the Checked property - they cannot be combined.

The property referenced by the CheckedItem, holds the value of the radio button which is checked.

In the example, the second radio button will be checked when the page loads. That's because the initial value of the Color property is "g". If you click another radio button, the property value will be updated immediately.

<dot:RadioButton CheckedItem="{value: Color}" CheckedValue="r" Text="R"/>
<dot:RadioButton CheckedItem="{value: Color}" CheckedValue="g" Text="G"/>
<dot:RadioButton CheckedItem="{value: Color}" CheckedValue="b" Text="B"/>

<p>Selected color: {{value: Color}}</p>
using System.Collections.Generic;

namespace DotvvmWeb.Views.Docs.Controls.builtin.RadioButton.sample2
{
    public class ViewModel
    {
        public string Color { get; set; } = "g";
    }
}

Sample 3: RadioButton's Changed Event

The RadioButton has the Changed event which is fired whenever the radio button is checked or unchecked.

Notice the CheckedItem and CheckedValue properties. The first radio button will set true to the Value property in the viewmodel, the second one will set false. The value binding in the CheckedValue must be used, otherwise the true and false values would be treated as strings.

<dot:RadioButton CheckedItem="{value: Value}" CheckedValue="{value: true}" Changed="{command: OnChanged()}" />
<dot:RadioButton CheckedItem="{value: Value}" CheckedValue="{value: false}" Changed="{command: OnChanged()}" />

<p>{{value: NumberOfChanges}}</p>
using System.Collections.Generic;

namespace DotvvmWeb.Views.Docs.Controls.builtin.RadioButton.sample3
{
    public class ViewModel
    {
        public bool Value { get; set; }

        public int NumberOfChanges { get; set; } = 0;

        public void OnChanged()
        {
            NumberOfChanges++;
        }

    }
}

Sample 4: Real World Sample

Final price is calculated by adding a tax to price of selected beverage. Prices are set in CheckedValues property and the total price is updated after any change by Changed event.

@viewModel DotvvmWeb.Views.Docs.Controls.builtin.RadioButton.sample4.ViewModel, DotvvmWeb

<h3>Fruits</h3>
<p>
	<dot:RadioButton CheckedItem="{value: PriceWithoutTax}" Changed="{command: UpdatePrice()}" 
					 CheckedValue="{value: 1.0f}" Text="Apple"/>
	<dot:RadioButton CheckedItem="{value: PriceWithoutTax}" Changed="{command: UpdatePrice()}" 
					 CheckedValue="{value: 3.0f}" Text="Lemon"/>
	<dot:RadioButton CheckedItem="{value: PriceWithoutTax}" Changed="{command: UpdatePrice()}" 
					 CheckedValue="{value: 6.0f}" Text="Orange"/>
	<dot:RadioButton CheckedItem="{value: PriceWithoutTax}" Changed="{command: UpdatePrice()}" 
					 CheckedValue="{value: 5.0f}" Text="Pineapple"/>
</p>

<h3>Tax</h3>
<p>
	<dot:RadioButton CheckedItem="{value: Tax}" Changed="{command: UpdatePrice()}" 
					 CheckedValue="{value: 5.0f}" Text="Reasonable"/>
	<dot:RadioButton CheckedItem="{value: Tax}" Changed="{command: UpdatePrice()}" 
					 CheckedValue="{value: 10.0f}" Text="Still quite reasonable"/>
	<dot:RadioButton CheckedItem="{value: Tax}" Changed="{command: UpdatePrice()}" 
					 CheckedValue="{value: 20.0f}" Text="European"/>
	<dot:RadioButton CheckedItem="{value: Tax}" Changed="{command: UpdatePrice()}" 
					 CheckedValue="{value: 40.0f}" Text="European in 10 years"/>
</p>

<p>Total price: ${{value: Price}}</p>

using System.Collections.Generic;
using DotVVM.Framework.ViewModel;

namespace DotvvmWeb.Views.Docs.Controls.builtin.RadioButton.sample4
{
    public class ViewModel : DotvvmViewModelBase
    {
        public float PriceWithoutTax { get; set; }

        public float Tax { get; set; }

        public float Price { get; set; }

        public void UpdatePrice()
        {
            Price = PriceWithoutTax + ((PriceWithoutTax / 100) * Tax);
        }

    }
}

Properties

Name Type Description Notes Default Value
property icon Checked Boolean Gets or sets whether the control is checked.
attribute
inner element
static value
bindable
default
 False
property icon CheckedItem Object Gets or sets the CheckedValue of the first RadioButton that is checked and bound to this collection.
attribute
inner element
static value
bindable
default
 null
property icon CheckedValue Object Gets or sets the value that will be used as a result when the control is checked. Use this property in combination with the CheckedItem or CheckedItems property.
attribute
inner element
static value
bindable
default
 null
property icon Enabled Boolean Gets or sets a value indicating whether the control is enabled and can be clicked on.
attribute
inner element
static value
bindable
default
 True
property icon GroupName String Gets or sets an unique name of the radio button group.
attribute
inner element
static value
bindable
default
property icon InputCssClass String Gets or sets a CSS class that will be appended on the rendered input element.
attribute
inner element
static value
bindable
default
 null
property icon ItemKeyBinding IValueBinding Gets or sets a property that retrieves an unique key for the CheckedValue so it can be compared with objects in the CheckedItems collection. This property must be set if the value of the CheckedValue property is not a primitive type.
attribute
inner element
static value
bindable
default
 null
property icon LabelCssClass String Gets or sets a CSS class that will be appended on the rendered label element.
attribute
inner element
static value
bindable
default
 null
property icon Text String Gets or sets the label text that is rendered next to the control.
attribute
inner element
static value
bindable
default

Events

Name Type Description
event icon Changed Command Gets or sets the command that will be triggered when the control check state is changed.

HTML produced by the control

With no Text or an inner content specified, the control renders just the radio button.

<input type="radio" data-bind="..." />

If there is a Text or an inner content, the label is rendered around the radio button.

<label>
  <input type="radio" data-bind="..." />
  Text or inner content
</label>