System-Defined Variables
Microsoft Dynamics NAV automatically declares and initializes several variables that you can use when you develop applications. The following table describes the system-defined variables.
| System-defined variable | Description |
|---|---|
Rec |
When a record is modified, this variable specifies the current record, including the changes that are made. |
xRec |
When a record is modified, this variable specifies the original values of the record, before the changes. |
CurrPage |
This variable specifies the current page. You can access the controls of the page through this variable and set the dynamic properties of the page and its controls. |
CurrReport |
This variable specifies the current report. |
RequestOptionsPage |
This variable specifies the request options page for the current report. |
In addition, some triggers, such as the OnFormat trigger of a control, have a parameter that is defined as a local variable.
Example
The following example shows how to use the Rec and xRec pair of records.
In an application, data is stored in two tables, a header table and a line table. The header table contains general information about, for example, sales orders, while the line table contains the specific order lines. The page that you use to enter information into the header table has fields that contain the customer’s address. These fields are related to the Customer table, and can be filled by using a lookup function in the field that establishes the relationship. In the header table, only the customer number is stored, and the other fields that have customer information, such as name and address, are retrieved from the Customer table when the Customer No. field is validated.
In some situations, the user should be able to change the customer number, and in other situations the user should not be able to change it. If the order has already been shipped, for example, the user should not be able to change the customer number. If there is an incorrect number on an order that has not been processed completely, the user should be able to correct the error.
You could use the Rec and xRec variables to design your application in the following way:
When validating the customer number field, check whether the order has shipped.
If the order has shipped, compare the customer number fields in the xRec and Rec records. If they differ, reject the change.