Navigation
Multiple pages are generated as part of the overall view. Five multi-page navigation models are shown in the AllControls
sample:
NavigationPage using push/pop
NavigationPage Toolbar
TabbedPage
CarouselPage
MasterDetail
NavigationPage using push/pop
The basic principles of implementing push/pop navigation are as follows:
Keep some information in your model indicating the page stack (e.g. a list of page identifiers or page models)
Return the current visual page stack in the
pages
property ofNavigationPage
.Set
HasNavigationBar
andHasBackButton
on each sub-page according to your desireDispatch messages in order to navigate, where the corresponding
update
adjusts the page stack in the model
let view model dispatch =
View.NavigationPage(pages=
[ for page in model.PageStack do
match page with
| "Home" ->
yield View.ContentPage(...).HasNavigationBar(true).HasBackButton(true)
| "PageA" ->
yield View.ContentPage(...).HasNavigationBar(true).HasBackButton(true)
| "PageB" ->
yield View.ContentPage(...).HasNavigationBar(true).HasBackButton(true)
])
NavigationPage Toolbar
A toolbar can be added to a navigation page using .ToolbarItems([ ... ])
as follows:
let view model dispatch =
...
View.NavigationPage(pages =
[ View.ContentPage(...)
.ToolbarItems([View.ToolbarItem(text = "About", command = (fun () -> dispatch (ShowAbout true))) ] )
Example: Modal pages by pushing an extra page
A modal page can be achieved by yielding an additional page in the NavigationPage. For example, here is an “About” page example:
type Model =
{ ShowAbout: bool
...
}
type Msg =
| ...
| ShowAbout of bool
let view model dispatch =
...
let rootPage dispatch =
View.ContentPage(title = "Root Page", content = View.Button(text = "About", command = (fun () -> dispatch (ShowAbout true))))
let modalPage dispatch =
View.ContentPage(title = "About",
content= View.StackLayout(
children = [
View.Label(text = "Fabulous!")
View.Button(text = "Continue", command = (fun () -> dispatch (ShowAbout false) ))
]))
View.NavigationPage(pages=
[ yield rootPage dispatch
if model.ShowAbout then
yield modalPage dispatch
])
TabbedPage navigation
Return a TabbedPage
from your view:
let view model dispatch =
View.TabbedPage(children = [ ... ])
CarouselPage navigation
Return a CarouselPage
from your view:
let view model dispatch =
View.CarouselPage(children = [ ... ])
MasterDetail Page navigation
Return a FlyoutPage
from your view:
let view model dispatch =
View.FlyoutPage(
flyout = View.ContentPage(title ="flyoutPage", ...), // 'title' is needed for the flyout page
detail = View.ContentPage(...)
)
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