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.

page.dothtml
ViewModel.cs

<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.

page.dothtml
ViewModel.cs

<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.

page.dothtml
ViewModel.cs

<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.

page.dothtml
ViewModel.cs

@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);
        }

    }
}

Show all inherited properties

Properties

Name	Type	Description	Notes	Default Value
Checked	Boolean	Gets or sets whether the control is checked.	attribute inner element static value bindable default	False
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
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
ClientIDMode	ClientIDMode	Gets or sets the client ID generation algorithm.	attribute inner element static value bindable default	Static
DataContext	Object	Gets or sets a data context for the control and its children. All value and command bindings are evaluated in context of this value. The DataContext is null in client-side templates.	attribute inner element static value bindable default	null
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
GroupName	String	Gets or sets an unique name of the radio button group.	attribute inner element static value bindable default
ID	String	Gets or sets the control client ID within its naming container.	attribute inner element static value bindable default	null
IncludeInPage	Boolean	Gets or sets whether the control is included in the DOM of the page.	attribute inner element static value bindable default	True
InnerText	String	Gets or sets the inner text of the HTML element. Note that this property can only be used on HtmlGenericControl directly and when the control does not have any children.	attribute inner element static value bindable default	null
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
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
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
Text	String	Gets or sets the label text that is rendered next to the control.	attribute inner element static value bindable default
Visible	Boolean	Gets or sets whether the control is visible. When set to false, `style="display: none"` will be added to this control.	attribute inner element static value bindable default	True

Events

	Name	Type	Description
	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>

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