Chain of Command Notes - arp6333/xplusplus GitHub Wiki

final class SalesEditLines_Extension
{
    ...
}

[ExtensionOf(...)]
final class SalesEditLines_Extension
{
    ...
}

Class:               classStr(-NameOfBaseClass-)

Table / Data entity: tableStr(-NameOfBaseTable-)

Form:                formStr(-NameOfBaseForm-)

Form Datasource:     formDataSourceStr(-NameOfBaseForm-, -NameOfDataSource-)

Form Data field:     formDataFieldStr(-NameOfBaseForm-, -NameOfDataSource-, -NameOfField-)

Form control:        formControlStr(-NameOfBaseForm-, -NameOfControl-)

/// <summary>
/// Example Extension of a form DataSource.
/// Here, are extending the SalesParmLine DataSource in the SalesEditLines Form.
/// </summary>
[ExtensionOf(formDataSourceStr(SalesEditLines, SalesParmLine))]
final class SalesEditLinesSalesParmLine_Extension
{
    /// <summary>
    /// Random extendable method chosen for example.
    /// </summary>
    public void selectionChanged()
    {
        // 'next' keyword is required to continue the chain
        // It does not have to be at the beginning; it can be before, after, or anywhere in-between our code depending on desired use case
        next selectionChanged();

        // If the method has a return value, we can set it to a variable and return it later, like such:
        bool result = next selectionChanged();
        // ... our code here, which could include modifying the value of 'result' ...
        return result;


	// Getting the extended datasource / control
        // 'this' keyword will all depend on what exactly you are extending
        // (extending DS, this = datasource; extending form control, this = form control; etc)
 	FormDataSource  formDS           = any2Object(this) as FormDataSource;
 	FormControl     control          = any2Object(this) as FormControl;

        // Getting the currently selected table record, if applicable
 	SalesParmLine   SalesParmLine    = formDS.cursor();

 	
	// Get the form run - we can then use this can extract lots of information from the form such as other controls and datasources
	FormRun         formRun          = control.formRun(); // or formDS.formRun()

	// Get another datasource from the same parent form	
        // formRun.dataSource(formDataSourceStr(-FormName-, -DataSourceName-))
 	FormDataSource      SalesParmTableDS = formRun.dataSource(formDataSourceStr(SalesEditLines, SalesParmTable));

	// Get a control from the parent form
        // formRun.design().controlName(formControlStr(-FormName-, -ControlName-))
        // We can use the 'as' keyword to assign it to any type of FormControl, this example just uses the FormDateControl
	FormDateControl dateControl      = formRun.design().controlName(formControlStr(SalesEditLines, DateControl)) as FormDateControl;

        // To access a form variable, you can use 'element'
        // For example, if the main form has a variable declared 'str stringVariable' it can be retrieved in the extension using:
        str stringVariable = element.stringVariable;
    }

}