Reference Selector

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The reference selector is an input widget that can be used to display and edit associations.

The reference selector is similar to a Report Parameter except that it allows users to choose from a list of objects with which to fill an association rather than items listed in an enumeration. The selector requires you to choose an entity with which the parent object shares a reference. It will also require you to choose which attribute from that referenced entity you wish to display in the selector.

General Properties

Select Using

The reference selector allows the end user to select objects by using either a drop-down or a pop-up page. If you choose to select using a page, the drop-down functionality will be replaced with a button to the right of the widget that will open a selection pop-up.

Value Description
Page Select the reference using a pop-up page.
Drop-down Select the reference using a drop-down.

Default value: Drop-down

Empty Option Caption

This property represents the caption for the empty option in the drop-down reference selector shown to the user. Setting the caption is not available if the Select Using property set to the Page option. This is a translable text. For more details, see Translatable Texts.

Select Page

The select page property determines which page is opened when the select page button is used. This page can be used to select associated objects from the list of all possible objects. This page should contain a data grid, template grid or list view connected to the same entity as the input reference set selector.

See Opening Pages. Note that opening select pages in content is prohibited.

Go-To Page

The go-to page gives end users quick access to a more detailed overview of the object being selected. This property determines which page is shown to the user. The page should contain a data view with the same entity as the one that is selected by the reference selector.

Go-To Page Settings

These settings specify how the page is opened.

See Opening Pages for more details.

Validation Properties

{% markdown %} The **Validation type** and **Validation message** properties were introduced in 7.6.0. They supersede the **Required** and **Required message** properties. {% endmarkdown %}

Validation Type

This property indicates whether this widget value should be validated and, if so, how. The possible options are no validation, a predefined validation, or a custom validation.

The possible values of a predefined validation are the following: * Required – all data types * E-mail – string * Positive number – decimal, float, integer, long * Date in the future – dateTime * Date in the past – dateTime

Custom validations are expressions that follow the Microflow expression syntax. Both $currentObject and $value are in a scope that refers to the current object and the current member value, respectively.

When a validation is set and it fails for this widget, a message will be shown when the user selects Save.

Default value: (none)

Validation Message

This property determines the message that is shown to the user if widget validation is enabled and has failed. This is a translable text (for more information, see Translatable Texts).

{% markdown %} For example, if an address field is required, the validation message for the text box of the address could be something like, "The address is required." {% endmarkdown %}

Required

This property indicates whether this widget must be filled in by the end user or not. If set to true, this widget cannot be left empty, and a message will be shown if the user selects Save.

Default value: False

Required Message

This property determines the message that is shown to the user if the widget is empty and the Required property is set to true. This is a translable text (for more inforamtion, see Translatable Texts).

{% markdown %} For example, if an address field is required, the required message for the text box of the address could be something like, "The address is required." {% endmarkdown %}

Formatting Properties

Decimal Precision (Only for Numeric Attributes)

The precision of a value describes the number of digits that are used to express that value. This property indicates the number of decimal places (the number of digits following the point).

Default value: 2

Group Digits (Only for Numeric Attributes)

For ease of reading, numbers with many digits before the decimal separator may be divided into groups using a delimiter. This property determines whether or not such a delimiter is used. Which delimiter is used depends on the language of the end user.

Default value: No

Date Format (Only for Attributes of Type Date and Time)

The date format determines whether the reference selector displays the date, time, date and time, or a custom variation of the linked attribute. How the date and/or time are formatted depend on the localization of the user viewing the data.

Default value: Date

Selectable Objects Properties

The properties in the category ‘Selectable objects’ determine the objects out of which the end user can make a selection. There are two, mutually exclusive, ways of influencing the selectable objects:

  1. A microflow returns the list of selectable objects.
  2. The list of objects is determined automatically taking into account the context mechanism and the properties that influence that mechanism.

Microflow

If a microflow is selected, the microflow will be called to compute the list of objects that the reference selector will show. A microflow can only be used if the selection is made using a drop-down.

Microflow Settings

In the microflow settings you can specify what parameters to pass to the microflow.

XPath Constraint

With the XPath constraint you can add a manual constraint to limit the list of objects that can be selected.

This property has no effect if a microflow is used to fill the reference selector.

Constrained By

A reference selector can be constrained by one or more paths. This is typically used to make one reference selector dependent on another. For example, in page where you can edit an order line, a product selector can be constrained by a category selector. After selecting a category, the product selector is constrained by this category and shows only products in the category.

This property has no effect if a microflow is used to fill the reference selector.

Sort Order

The sort order specifies the order in which the items in the reference selector are shown. You can sort on multiple attributes in both directions (ascending and descending). If no sort order is specified, the reference selector sorts on the displayed attribute.

Default value: No sort order

Data Source Properties

Attribute Path

The attribute path specifies which attribute of an associated entity is shown in the reference selector. The path must follow one association of type reference starting in the entity of the data view.

Label properties

A label can be used to described the purpose of the widget to the user. The label is shown next to the widget in the user interface. If a label is configured, the widget will be rendered in the browser wrapped in a form group. See Bootstrap documentation.

Show label

This property determines whether the label is rendered and the widget is wrapped in a form group.

Default value: No

Label caption

This property is shown only when Show label is Yes. This property determines what text is rendered within a label.

Editability Properties

Editable

The editable property indicates whether the end user will be able to change the value displayed by the widget.

Value Description
Default The value is editable if security allows it (i.e. if the user that is signed in has write rights to the selected attribute).
Never The value is never editable.
Conditional The value is editable if the specified condition holds. (see below)
  • Default value: Default

Read-only style

This property determines how the widget is rendered if it is read-only.

Value Description
Set by data view Set to Control or Text by the containing data view.
Control Widget is displayed but disabled so the value cannot be modified.
Text Widget is replaced by a textual representation of the value.

Default value: Set by data view

Condition

The widget can be made editable only if the object of the data view that contains the widget satisfies the specificied criteria.

A practical example would be a personal details form in which the user must enter his marital status. In this case, you might wish to disable an input for the marriage date until the user indicates that he or she is married.

Based on Attribute Value

When selected, this enables the widget while a particular attribute has a certain value. Only Boolean and enumeration attributes can be used for this purpose.

Based on Expression
Added in Mendix 7.1.

When selected, this enables the widget while a provided expression evaluates to true. The object of the containg data view is available inside an expression as a $currentObject variable.

Note that the expression is evaluated in the browser, and hence, we advise against using “secret” values (like access keys) in it. In particular, we disallow usages of constants. Also, client-side expressions currently do not support all the functions that are available in the microflows. Please refer to an autocomplete list to know what functions are supported in your version.

Visibility Properties

Visible

By default, whether or not an element is displayed in the browser is determined by how the page is designed and the user’s roles within the application. However, the page can be configured to hide the element unless a certain condition is met.

Context

The widget can be made visible only if the object of the data view that contains the widget satisfies the specificied criteria.

A practical example would be a web shop in which the user must submit both billing and delivery information. In this case, you might not wish to bother the user with a second set of address input fields unless they indicate that the billing address and delivery address are not the same. You can accomplish this by making the delivery address fields conditionally visible based on the Boolean attribute SameBillingAndDeliveryAddress.

Based on Attribute Value

When selected, this shows the widget while a particular attribute has a certain value. Only boolean and enumeration attributes can be used for this purpose.

Based on Expression
Added in Mendix 7.1.

When selected, this shows the widget while a provided expression evaluates to true. The object of the containing data view is available inside an expression as a $currentObject variable.

Note that the expression is evaluated in the browser, and hence, we advise against using “secret” values (like access keys) in it. In particular, we disallow usages of constants. Also, client-side expressions currently do not support all the functions that are available in the microflows. Please refer to an autocomplete list to know what functions are supported in your version.

Module Roles

The widget can be made visible to a subset of the user roles available in your application. When activated, this setting will render the widget invisible to all users that are not linked to one of the selected user roles.

Events Properties

On change

The on-change property optionally specifies a microflow that will be executed when leaving the widget after the value has been changed.

On change settings

The on change settings specify what parameters are passed to the microflow, whether a progress bar is shown and more.

See Starting Microflows.

Common Properties

Name

The internal name of the widget. You can use this to give sensible names to widgets. The name property also appears in the generated HTML: the widget DOM element automatically includes the class ‘mx-name-{NAME}’, which can be useful for Selenium testing.

Class

The class property allows you to specify a cascading style sheet (CSS) class for the widget. This class will be applied to the widget in the browser and the widget will get the corresponding styling. The class should be a class from the theme that is used in the project. It overrules the default styling of the widget.

Note that the styling is applied in the following order: 1. Default styling defined by the theme the project uses. 2. The 'Class' property of the widget. 3. The 'Style' property of the widget.

Style

The style property allows you to specify additional CSS styling. If a class is also specified, this styling is applied after the class.

background-color:blue; This will result in a blue background

Tab index

The tab index influences the order in which the end user navigates through the page using the tab key. By default tab indices are zero and the tab order is determined automatically by the client system. A value of minus one (-1) means that the widget will be skipped when tabbing through the page.

Default value: 0

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