Checked Binding

The Kendo UI Checked (checked) binding checks or unchecks a checkbox (<input type="checkbox" />) or a radio button (<input type="radio" />) based on a value from the View-Model.

The checked binding supports only checkable DOM elements and widgets. To set the value of other input elements, use the value binding.

Using with Checkboxes

The Kendo UI MVVM displays a bound checkbox in checked state if the value from the View-Model is true. If the checkbox is checked by the end-user, the value from the View-Model is set to true. Unchecking the checkbox sets the value from the View-Model to false. Setting the value from the View-Model via code checks or unchecks the checkbox depending on the new value.

The following example demonstrates how to use the checked binding with a checkbox. The checkbox is initially displayed as unchecked because the value of the isChecked field is false. If the user checks the checkbox, the isChecked field is set to true. Setting isChecked to true from code checks the checkbox. Setting isChecked to false unchecks it.

<input type="checkbox" data-bind="checked: isChecked" />
<script>
var viewModel = kendo.observable({
    isChecked: false
});

kendo.bind($("input"), viewModel);
</script>

Binding Lists of Checkboxes to Arrays

The checked binding also supports binding a list of checkboxes to a View-Model value of an array type. Checking a checkbox from the list appends its value attribute to the array specified by the checked binding. Unchecking a checkbox removes its value attribute from the array.

The following example demonstrates how to use the checked binding with a list of checkboxes. The first checkbox is checked after calling kendo.bind because its value attribute ("Red") is present in the colors array specified by the checked binding. Checking another checkbox from the list, e.g. "Blue", would append its value attribute ("Blue") to the colors array. Unchecking a checkbox from the list would remove its value attribute from the colors array.

<input type="checkbox" value="Red"   data-bind="checked: colors" />
<input type="checkbox" value="Green" data-bind="checked: colors" />
<input type="checkbox" value="Blue"  data-bind="checked: colors" />
<script>
var viewModel = kendo.observable({
    colors: ["Red"]
});

kendo.bind($("input"), viewModel);
</script>

Using with Radio Buttons

The Kendo UI MVVM displays a radio button in checked state only if its value attribute is equal to the value from the View-Model. If the user checks a radio button, its value attribute updates the corresponding value from the View-Model. Updating the value from the View-Model via code checks the radio button whose value attribute is equal to the new value.

The following example demonstrates how to use the checked binding with a group of radio buttons. The second radio button is checked after calling kendo.bind because its value attribute ("Green") is equal to the value of selectedColor. Checking another radio button, for example, "Blue", updates selectedColor (to "Blue"). The name attribute of all radio buttons is the same.

All radio buttons which act as a group have to have the same name attribute. Only then checking a radio button from the group unchecks the previously checked one.

<input type="radio" value="Red"   name="color" data-bind="checked: selectedColor" />
<input type="radio" value="Green" name="color" data-bind="checked: selectedColor" />
<input type="radio" value="Blue"  name="color" data-bind="checked: selectedColor" />
<script>
var viewModel = kendo.observable({
    selectedColor: "Green"
});

kendo.bind($("input"), viewModel);
</script>

Using with Data-Type Attributes

Checkbox inputs bound to an array and radio buttons also support strong typing, which uses the same principles applied to the strongly typed value binding.

    <div id="view">
        <input type="checkbox" name="items" data-bind="checked: items" value="bike"/>
        <input type="checkbox" name="items" data-bind="checked: items" value="-1" data-type="number"/>
        <input type="checkbox" name="items" data-bind="checked: items" value="true" data-type="boolean"/>
        <input type="checkbox" name="items" data-bind="checked: items" value="2015-01-31" data-type="date"/>

        <input type="radio" name="group" data-type="date" data-bind="checked: group" value="2015-01-31"/>
        <input type="radio" name="group" data-type="datetime-local" data-bind="checked: group" value="2013-06-05T23:13:40"/>
        <input type="radio" name="group" data-type="text" data-bind="checked: group" value="Hello"/>
        <input type="radio" name="group" data-type="number" data-bind="checked: group" value="3.14"/>
        <input type="radio" name="group" data-type="boolean" data-bind="checked: group" value="false"/>
    </div>
    <script>
        var viewModel = kendo.observable({
            items: [-1, true],
            group: kendo.parseDate("2015-01-31", "yyyy-MM-dd")
        });
        kendo.bind($("#view"), viewModel);
        viewModel.bind("change", function(e){
            console.log(e.field, "=", this.get(e.field));
        });
    </script>

See Also

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