Add SwitchPresenter Control

[michael-hawker]

I'm submitting a...

• Feature request (UserVoice request: https://wpdev.uservoice.com/forums/110705-universal-windows-platform/suggestions/33684469-add-switchpresenter-control)

Problem

When providing a choice to the user, like picking a check-in method:

It could be handy to be able to swap out controls with XAML vs having to create separate complex visual states or logic to handle the dynamic UI changes.

Solution

The SwitchPresenter control would act as a switch statement for XAML providing a dynamic way to change out content based on some other value.

     <ComboBox x:Name="Lookup" Header="Look up reservation" SelectedIndex="0">
            <x:String>Select an option</x:String>
            <x:String>Confirmation Code</x:String>
            <x:String>E-ticket number</x:String>
            <x:String>Mileage Plan number</x:String>
     </ComboBox>
     <controls:SwitchPresenter Value="{x:Bind Lookup.SelectedItem}">
            <controls:Case Value="Confirmation Code">
                    <TextBox Name="ConfirmationCodeValidator"
                                    extensions:TextBoxRegex.Regex="^[a-zA-Z]{6}$"
                                    Header="Confirmation code"
                                    PlaceholderText="6 letters" />
            </controls:Case>
            <controls:Case Value="E-ticket number">
                    <TextBox Name="TicketValidator"
                                    extensions:TextBoxRegex.Regex="(^\d{10}$)|(^\d{13}$)"
                                    Header="E-ticket number"
                                    PlaceholderText="10 or 13 numbers" />
            </controls:Case>
            <controls:Case Value="Millage Plan number">
                    <TextBox Name="PlanValidator"
                                    Header="Mileage Plan #"
                                    PlaceholderText="Mileage Plan #" />
            </controls:Case>
            <controls:Case IsDefault="True">
            </controls:Case>
     </controls:SwitchPresenter>

[skendrot]

That looks even more complex than what I use today which is a simple converter that checks equality

[michael-hawker]

@skendrot this example is a bit contrived, but the presenter only shows the active case in the visual tree, so you don't have a bunch of other things around with visibility converters. Kind of like a Frame. Though it also provides structure to the XAML it so it's clear there's a switch happening vs. a bunch of textbox controls wondering when each would be displayed.

You also have a default case and could provide a binding as a value for a case too if you want more complex scenarios involving another value.

I could also add a Values for having a case be useable by multiples of the same type.

I'm using it in a scenario instead of a Frame for my NavigationView SelectedItem to swap out my sub-control.

[skendrot]

Not saying it's not useful. I'm saying it can already be accomplished today with a converter:

<TextBox Name="ConfirmationCodeValidator"
            extensions:TextBoxRegex.Regex="^[a-zA-Z]{6}$"
            Header="Confirmation code"
            PlaceholderText="6 letters"
            Visibility="{Binding SelectedItem, Converter={StaticResource EqualToVis}, ConverterParameter='Confirmation Code'}"/>
<TextBox Name="TicketValidator"
            extensions:TextBoxRegex.Regex="(^\d{10}$)|(^\d{13}$)"
            Header="E-ticket number"
            PlaceholderText="10 or 13 numbers"
            Visibility="{Binding SelectedItem, Converter={StaticResource EqualToVis}, ConverterParameter='E-ticket number'}"/>
<TextBox Name="PlanValidator"
            Header="Mileage Plan #"
            PlaceholderText="Mileage Plan #"
            Visibility="{Binding SelectedItem, Converter={StaticResource EqualToVis}, ConverterParameter='Mileage Plan number'}"/>

[maxkatz6]

It also can be done using x:DeferLoadStrategy=Lazy (or x:Load) and VisualStateManager with EqualsStateTrigger

[michael-hawker]

This is already checked-in but needs samples and docs still. I'll get to that soon.