[wojzeh]

суть сводится к

[FormDataSourceEventHandler(formDataSourceStr(<FormName>, <FormDataSourceName>), FormDataSourceEventType::Activated)]
    public static void FormDataSourceName_OnActivated(FormDataSource _sender, FormDataSourceEventArgs _e)
    {
        <FormDataSourceTable>       formDataSourceTable                 = _sender.cursor();
        FormRun                     formRun                             = _sender.formRun();
        FormDataSource              anyFormDataSource_ds                = formRun.dataSource(formDataSourceStr(<FormName>, <AnyFormDataSourceName>)) as FormDataSource;
        <AnyFormDataSourceTable>    anyFormDataSourceTable              = anyFormDataSource_ds.cursor();
        FormControl                 anyFormControl                      = formRun.design(0).controlName('AnyFormControlName');
        
        // your logic goes here, for example
        if(formDataSourceTable.enabled())
        {
            anyFormControl.visible(false);
            anyFormControl.enabled(!anyFormDataSourceTable.RecId);
        }
    }