Configuration

The value of this option will be passed to the accesskey attribute of the HTML element that underlies the widget.

This option is used when the widget is displayed on a platform whose guidelines include the active state change for widgets.

When you configure this option in an ASP.NET MVC Control, pass a dictionary as shown in the following code.

@(Html.DevExtreme()
    // other widget options
    // ...
    .ElementAttr(new Dictionary<string, object>() {
        { "id", "elementId" },
        { "class", "class-name" },
        // ...
    })
)

@(Html.DevExtreme().WidgetName() _
    .ElementAttr(New Dictionary(Of String, Object) From {
        { "id", "elementId" },
        { "class", "class-name" }
    })
)

This option accepts a value of one of the following types.

• Number
  The height of the widget in pixels.

• String
  A CSS-accepted measurement of height. For example, "55px", "80%", "auto", "inherit".

• Function
  A function returning either of the above. For example:

  JavaScript

  height: function() {
      return window.innerHeight / 1.5;
  }

When you configure this option in ASP.NET MVC Controls, pass a dictionary as shown in the following code.

@(Html.DevExtreme()
    // other widget options
    // ...
    .InputAttr(new Dictionary<string, object>() {
        { "id", "inputId" },
        // ...
    })
)

@(Html.DevExtreme().WidgetName() _
    .InputAttr(New Dictionary(Of String, Object) From {
        { "id", "inputId" }
    })
)

In Knockout apps, you may need to inform a user about an error that occurred during the validation of a view model field. For this purpose, set the editor's isValid option to the isValid value of the dxValidator that validates this field. To show an error message, set the editor's validationError option to the dxValidator's validationError value.

var editorValue = ko.observable("").extend({
    dxValidator: {
        validationRules: [{
            type: 'required',
            message: 'Specify this value'
        }]
    }
});
var viewModel = {
    editorOptions: {
        value: editorValue,
        isValid: editorValue.dxValidator.isValid,
        validationError: editorValue.dxValidator.validationError
    }
};

The editor's isValid and validationError options should also be specified when using a custom validation engine. In this instance, the validation result will be displayed for the editor by the means of the DevExtreme Validation UI.

See Also

• Validate View Model
• Use Custom Validation Engine
• Use Custom Validation Engine - MVVM Approach

When using the widget as an ASP.NET MVC Control, specify this option using the NumberBoxMode enum. This enum accepts the following values: Text and Number.

Specify this option if the widget lies within an HTML form that will be submitted.

If you configure the widget as an ASP.NET MVC Control, use this option to bind the widget to a model property. If this model property contains Data Annotation validation attributes, you get the client-side validation enabled by default.

Assign a function to perform a custom action when a change within the widget's input element is committed by an end user.

Assign a function to perform a custom action after the widget's input is copied.

Assign a function to perform a custom action after the widget's input is cut.

Assign a function to perform a custom action after the 'Enter' key is pressed within the widget's input element.

Assign a function to perform a custom action after the widget's input is focused.

Assign a function to perform a custom action after the widget's input element loses focus.

You cannot access elements in the widget because this handler is executed before they are ready. Use the onContentReady handler instead.

Assign a function to perform a custom action when a value within the widget's input element is changed by an end user.

Assign a function to perform a custom action when a key is pressed down within the widget's input element.

Assign a function to perform a custom action when the keypress DOM event is raised for the current input element.

Assign a function to perform a custom action when a key is released within the widget's input element.

Assign a function to perform a custom action after the widget's input is pasted.

Assign a function to perform a custom action when the editor value changes.

When this option is set to true, the widget text flows from right to left, and the layout of elements is reversed. To switch the entire application/site to the right-to-left representation, assign true to the rtlEnabled field of the object passed to the DevExpress.config(config) method.

DevExpress.config({
    rtlEnabled: true
});

The Clear button sets the widget value to null.

Each spin button click increases or decreases the widget value by the the value specified using the step option.

If the widget is displayed on a touch device, it uses touch-friendly spin buttons regardless of the current theme.

The option makes sense only if the showSpinButtons option is set to true.

The value of this option will be passed to the tabindex attribute of the HTML element that underlies the widget.

In Knockout approach, you may need to use an editor to inform end users that an error occurred during the validation of a ViewModel field. In this instance, set the editor's isValid option to the isValid property value of the dxValidator that validated the ViewModel's field. In addition, set the editor's validationError option to the validationError property value of the dxValidator object.

In the code, the login specified by an end user is validated on the level of the ViewModel. If validation of the login value fails, a validation message is displayed on the Login editor.

<div data-bind="dxTextBox: {
    value: login,
    isValid: login.dxValidator.isValid,
    validationError: login.dxValidator.validationError,
    placeholder: 'Login'
}"></div>

var viewModel = {
    login: ko.observable("").extend({
        dxValidator: {
            validationRules: [{ type: 'required', message: 'Login is required' }]
        }
    }),
    //...
}

The editor's validationError option, as well as the isValid option, should also be specified when using a custom validation engine. In this instance, the validation result will be displayed for the editor by the means of the DevExtreme Validation UI. For details, refer to the Use Custom Validation Engine topic.

The following option values are possible:

• auto
  The tooltip with the message is displayed when the editor is in focus.
• always
  The tooltip with the message is not hidden when the editor loses focus.

When using the widget as an ASP.NET MVC Control, specify this option using the ValidationMessageMode enum. This enum accepts the following values: Auto and Always.

The option takes on a string value representing a DOM event name or several DOM event names separated by a space. It is recommended that you use the "keyup", "blur", "change" and "focusout" events. However, you can use other DOM events for your own discretion.

This option accepts a value of one of the following types.

• Number
  The width of the widget in pixels.

• String
  A CSS-accepted measurement of width. For example, "55px", "80%", "auto", "inherit".

• Function
  A function returning either of the above. For example:

  JavaScript

  width: function() {
      return window.innerWidth / 1.5;
  }