Page triggers allow you to use C/AL code to control the behavior of the system as a result of an event on the page, such as a page opening or a field changing its value. You typically use page triggers for advanced validation and logic.
Page triggers can be divided into three categories:
- 
          General page triggers that apply to the entire page
- 
          Field page triggers that apply to a field control on a page
- 
          Action triggers that apply to an action on a page.
|  Important | 
|---|
| If you define two functions that have the same name, one defined in a page and the other in a table that is referenced by the page, you cannot invoke the function defined in the page directly. By default, a call to the function invokes the function that is defined in the table. This behavior occurs when the function is called from a source expression or a trigger. | 
General Triggers
The following table lists triggers that apply to the entire page.
| Page trigger name | Executed | 
|---|---|
| When the page is loaded, but before the controls are available. | |
| When the page is initialized and the controls are available. | |
| When the page about to close and after OnQueryClosePage Trigger trigger. | |
| When the page is opened and a record is retrieved from a table. | |
| When the page changes from displaying one record to another record in a table. For example, on a Customer card page, this happens when a user selects Next (Ctrl+Page Down) or Previous (Ctrl+Page Up). | |
| After the current record is retrieved from the table. | |
| When a record has been retrieved but not yet displayed. | |
| When a new record has been initialized but not yet displayed. | |
| When a new record is about to be inserted in the table. | |
| When a record is about to be modified in the table. | |
| When a record is about to be deleted from the table. | |
| When the page is about to close, but before the OnClosePage Trigger. | 
Field Triggers
The following table describes the triggers that are available on field controls.
| Control trigger | Executed | 
|---|---|
| When the user changes the value in a field and then selects away from the field so that the field loses focus. | |
| When the user requests a lookup by clicking a field's lookup button or pressing F4. | |
| When the user requests a drill-down by choosing the field's drill-down button or pressing Shift+F8. | |
| When the user requests assist-edit by choosing an AssistEdit button or by pressing Shift+F4. | |
| When a control add-in is initiated on a page. | 
Action Triggers
The following table lists triggers that apply to actions on a page.
| Triggers | Executed | 
|---|---|
| When an action is initiated on a page. | 





