History Management

Lesson 4 - Navigation Paths

Another important concept in History Management in DataFlex is Navigation Paths.
Navigation paths are used within the framework to determine how an app navigates from one view to the next. Each navigation path must be registered for the history management to function as intended.
To do this, an instruction called WebRegisterPath is used in a view or object that performs the navigation.
WebRegisterPath takes several parameters being:
eNavigationMode - The type of navigation to perform.
- Valid values are: ntNavigateForward, ntNavigateForwardCustom, nfNavigateBegin
hoNavigateView - The handle of the view object to navigate to
hoInvokingObject - (optional) By default Self
sStateKey - (optional) Custom state key to be used in the State Hash’s navigation path id
Finally, to perform the navigation a new instruction called Send NavigatePath is added.

DEMONSTRATION

To fix the navigation for a menu item and a button on a dashboard
Staring from the same example in Lesson 3…
First, find the menu item in our WebApp source, and register the navigation path:
WebRegisterPath ntNavigateBegin oVwPersonSelect
WebRegisterPath is called, ntNavigateBegin is sued to perform a NavigateBegin and oVwPersonSelect is where it is being navigated to.
Next, NavigatePath is called with Send NavigatePath.
Next, is the button on the dashboard (open Dashboard.wo), which is largely treated the same way.
WebRegisterPath ntNavigateForward oVwPersonSelect
So WebRegisterPath is called, ntNavigateForward is used to perform a Forward navigation this time
and tell it once again to navigate to oVwPersonSelect.
Send NavigatePath is also used here.
Compile and run the application to show that the menu item shows oVwPersonSelect, and the button on the dashboard does the same.