DataSaving

This rule is triggered by a user or by code before calling the API to save the current datasource. This happens when :

• the user clicks on the Save button
• calling the SaveDataAsync method

Validation rules are triggered after this rule and can stop the save operation.

Note

In most cases, this rule should be set on server-side at the entity view level.
A good reason to set this rule on client-side rule is to avoid making an unnecessary API call.

Multiple APIs will be called depending on the type of changed made:

• POST when creating a new item
• PUT when updating an existing item
• DELETE when deleting an item in a collection that is not embedded

See this article for more information on event rules execution order.

Behavior in a master / detail view

In a master / detail UI, when both the main UI view and the detail UI view have a DataSaving event rule, the rule of the master element UI view is always executed. This is the case whether you only make changes on the detail items or not.
However, the rule of the details UI view is only executed when saving changes made to the detail items if the collection is not embedded.

Arguments

The Arguments property provides the following options.

Name	Type	Description
Cancel	bool	If set to true, the API will not be called.

Item versus DatasourceCurrent

Since the rule is not tied to a specific item, the Item property does not exist in this rule. However, you should properties CreatedItems and ModifiedItems to access the created and modified items.
DatasourceCurrent refers to the item at the current position in the datasource.

To know more on the difference between the Item and DatasourceCurrent properties in an UI view event rule, you can check this article.