List Box Control

1. Create a view.
2. Drag the control onto the canvas. You can find the control in the Input section of the Toolbox.
3. Add a data source to your control. To do this, configure the Type under the Data Source of the Properties section.
4. Configure the rest of the properties as necessary.
5. Run the view.

Configuring a Data Source for the Control

When you click on the ellipsis next to Data Source > Type in the control's Properties, the Configure Data Source page opens. You can use a SmartObject or a static list of values.

Fields	Description
Use a static list of values in the control	You can create a static list of items for the control. These values are stored as text in the K2 database. Select the option and then click the ellipsis next to List Items to configure your static list.
List Items	Click the ellipsis next to List Items to configure the list of static values for the control.
Use a SmartObject as data source	Select this option if you want to use a SmartObject as the data source.
SmartObject	Select the SmartObject that you want to use to populate the control. Click the ellipsis next to SmartObject to select one.
Method	The method that you want to use to populate the control.
Value	The SmartObject property that you want to use as the value in the control.
Cache the data	Select this option if you want to cache the data which allows for client side filtering when the form is offline.
Default Value	The default SmartObject value to be used.
Show items from the selected SmartObject	Select this option if you want to show items from the main SmartObject.
Display	The SmartObject property to display.
Show items from an associated SmartObject	Select this option if you want to show items from an associated SmartObject.
Lookup SmartObject	An optional SmartObject that you want to use as the source of the display values. Click on the ellipsis to select the SmartObject.
Lookup Method	The method that you want to use on the lookup SmartObject when retrieving the display values.
Source Join Property	The SmartObject property on the main SmartObject that is used to join the original SmartObject with the Lookup SmartObject.
Lookup Join Property	The SmartObject property on the lookup/associated SmartObject that is used to join the SmartObjects.
Display	The SmartObject property to display. Select the item by clicking on the ellipsis.

List Box items per row or column

Use the Stacked by and No. of items Properties to specify the amount of rows or columns to display. When you select to stack by rows, the first row starts from left to right until the number of items per row is reached, and then a new row is created. When you stack by columns, the first column starts from top to bottom until the number of items per column is reached, and then a new column is created. You can find these properties in the Settings section:

The image below shows an example of stacking three items per row:

The image below shows an example of stacking three items per column:

Client Side Filtering

You have the option to cache the SmartObject data to enable client-side filtering. This is especially useful when you use a form on a mobile device and you need the data to be available if the device is offline. The control's data set is populated on initial load (from the server) any other changes to the underlying data source's data does not reflect in the current session until another server call is forced to update the data set. To enable the caching of data, select the Cache the data option on the Configure Data Source page.

How caching is applied

You don't have to configure anything except select the Cache the data option to enable caching. The rules are automatically configured by the server. You can, however, remove these rules and place them somewhere else depending on your needs. This is an explanation of how caching is applied by the system.

Below is a diagram of how the caching is applied in the background to enable client-side filtering.

When you select the Cache the data option, the following two actions are added to the When the View executed Initialize rule event:

• Load [List Box ] list control cache with data
• Populate [List Box ] list control with cached data

The following steps refer to the diagram shown above and describe what happens in the background when caching is applied:

When you access a form on a mobile device, the view initializes and the rule action to Load list control cache with data executes as shown in point 1. Next, the rule action to populate list control with cached data executes as indicated in point 2. You can select updated data from the list on the form. When the device goes offline, you can still access the information in the list.

Additional records added to the data set will not reflect until cached data is loaded again.

You can find the control in the Input section of the Toolbox.

The control interacts with other controls through rules. When you bind properties between different controls, you can use the data to populate properties or set values. Use the following examples for when to use the control with other controls through rules:

• Populate a list control with data: You can populate the control if its data source is a SmartObject
• Set a control’s properties: You can configure the settable properties of the control with this action
• Show/Hide: The Visible property allows you to show or hide the control through rules
• Enable/Disable: The Enabled property allows you to enable or disable the control through rules
• Data Transfer: You can transfer data from items listed in the context browser to the control
• For-each looping conditions: You can use the control in for-each loop conditions
• Specify the edit state of view and form controls: You can specify if controls must be read only or editable.

The following events and methods are available on the control:
Rule Events:

• When [control] is Changed: This event executes when the control is set to a new value that is different from the previous value. You can use this event to trigger actions when the control is changed, for example when an item is changed, then set the properties of another control.
• When [control] is Double-Clicked: You can execute a rule condition or action when the control is double-clicked, for example populate another control or open a subview.
• When [control] is Initializing: While you can see this event in the Rule Designer, it has been deprecated. Instead use the When the View/Form Initialize event.
• When [control] is Populated: This event executes each time the control is loaded. You can execute a rule condition or action when the control loads such as set focus to the control.
• When [control] is Set: This event executes each time the control is set to any value regardless of if the previous value is the same. You can use this for updating cascading controls.

Control Methods:

• Execute a [control's] Focus method: You can use the Focus control method to set focus to the control in runtime.
• Execute a [control's] Select All method: Selects all items in the list. You can use this method for example when a button is clicked.
• Execute a [control's] Unselect All method: Deselects all items in the list. Use this if you want to clear the list selection.

• You cannot filter the control according to another control's value
• If you select Multiple in the Selection Mode property and one in the Maximum Selection property, you have to deselect a value before you can select another value
• If you select Single in the Selection Mode property and one in the Maximum Selection property, you can select another value without deselecting the previous value. Simply click on the next value to deselect the previous
• If you configure multiple defaults for the control and you select Multiple in the Selection Mode property and 1 in the Maximum Selection property, the first default value is selected