Auto focus on page load

[AmelBawa-msft]

Summary of the pull request

• Added missing AutoFocusBehavior.cs behavior class. We can potentially delete this if in the behavior class was ported in a future release.
  • Port AutoFocusBehavior Behavior CommunityToolkit/Windows#443
• Set auto focus on app install page.
• Updated existing pages

References and relevant issues

https://task.ms/50153184

Detailed description of the pull request / Additional comments

Validation steps performed

PR checklist

• Closes #xxx
• Tests added/passed
• Documentation updated
• Telemetry compliance tasks completed for added/updated events

[krschau]

Is this the same thing @dhoehna implemented manually? Can we replace that with this?

[dhoehna]

Is this the same thing @dhoehna implemented manually? Can we replace that with this?

Amir petitioned for behaviors instead of pages. I'm okay with either approach to auto focus as long as new pages only need to do one extra thing to get auto-focus behavior.

However, only one approach should be used.

@AmelBawa-msft how will new pages and existing pages opt-in to using auto-focus behavior?

[krschau]

@dhoehna @AmelBawa-msft Can we do both? I like how simple the behavior is / someday we could just get it from CommunityToolkit, but agree that we don't want every dev to have to add something to every page they create. Instead of putting <commonBehaviors:AutoFocusBehavior /> only on one page, should we put it on DevHomePage.xaml so everyone gets it?

[dhoehna]

An issue Amir had with my implementation is a lack of control. On the environments pages and the app pages, focus needs to be moved after the UI is loaded. If this change allows child pages to DevHome "Please load me know" cool.

Otherwise, I don't agree on having two solutions solving the same auto-focus problem. I am fine with either approach, but only 1.

EDIT:
Amir, if you feel strongly about your solution then please update all the pages and remove DevHome* views.

[AmelBawa-msft]

@krschau , @dhoehna, we don't have a XAML for the parent class. I vaguely remember that inheritance was non-trivial or maybe not possible when the parent class has a corresponding XAML page. Agree with Darren, I do prefer a single solution, and they both seem to be doing the same identical thing, but one from XAML and the other from code-behind. I do prefer to put things in XAML as much as possible and maintain minimal code/logic in code-behind, promoting simplicity and reusability.

I will go ahead and update the other pages.

@dhoehna, I don't fully recall what was your use case, but I also found FocusBehavior:

This behavior sets the focus on the first control of Targets which accepts it. The focus will be set following the Targets order. The first control being ready and accepting the focus will receive it. The focus can be set to another control with a higher priority if it loads before FocusEngagementTimeout.

Usage:

<interactivity:Interaction.Behaviors>
    <behaviors:FocusBehavior>
        <behaviors:FocusTarget Control="{x:Bind myTextBox}" />
        <behaviors:FocusTarget Control="{x:Bind myButton}" />
    </behaviors:FocusBehavior>
</interactivity:Interaction.Behaviors>

<TextBox x:Name="myTextBox" />
<Button x:Name="myButton" />

[dhoehna]

@dhoehna, I don't fully recall what was your use case, but I also found FocusBehavior:

Shimmer and loading adaptive cards. In these cases the UI finished loading before theViewModel is done getting information. This causes the auto-focus to sometimes focus on the wrong element.