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I’m just coming back from Build 2014 and it was a great pleasure to talk to customers/developers.  It is one of the best parts of my job right now in seeing how customers use the technology our team represents.  If you are a XAML developer and didn’t have a chance to go to Build or haven’t watched all the sessions, here’s a quick short list of recommendations I’d have:

There are many more (app model, localization, accessibility, tiles, notifications, etc.) so please do look at the event site and download/watch your favorites.  I think the list above gives you a good intro to the UI area changes and introduction to the concepts of Universal Windows apps.  If you haven’t heard of that concept yet, you can jump to the Keynote from Day 1 for the quick demo.

Add Reference

The last session above is one that I want to write about today in this post.  In current form, a Universal Windows app in Visual Studio Update 2 allows you to maximize your sharing of code/assets across your Windows Store and Windows Phone app.  If you are like most developers, you rely on a great ecosystem of libraries and SDKs to augment your app and add functionality, UI or make things easier to develop.  In our keynote sample, the app we migrated (SportsLeague app) used JSON.NET and we showed that we are able to re-use the same library (which in this case happened to be a Portable Class Library, aka PCL) across the different endpoints.

One thing that is important is that you will need to add these references to each of your project ‘heads’ (the term we use to describe each endpoint in a shared project solution).  For some that are using direct binary DLL references to PCL libraries should be okay.  For others that are using Extension SDKs and/or NuGet packages, you may find yourself into some scenarios where either the SDK is different or the NuGet package isn’t updated yet to understand the Windows Phone 8.1 project type.  There are a number of these that are already updated like JSON.NET, Caliburn.Micro, etc.  If you find yourself using a library that isn’t updated yet, you may want/need to prod the author to update.  Better yet, if it is Open Source, submit a pull request with the update yourself!

SQLite or other native Extension SDKs

The other category are things that might be platform-specific and/or native.  These things are generally more complex than something that might work in a PCL and have dependencies on various native compiler/linker options or have been compiled in such a way that are different for the Phone device versus a tablet device.  One such example is SQLite.

SQLite is an in-process library that implements a self-contained, serverless, zero-configuration, transactional SQL database engine. The code for SQLite is in the public domain and is thus free for use for any purpose, commercial or private. SQLite is currently found in more applications than we can count, including several high-profile projects.

SQLite links against the C++ Runtime and as such needs to make sure the right linking happens for the phone and tablet CRT profiles.  Right now, the SQLite for Windows Phone Runtime 8.1 is in some testing, but since a lot of people have been asking me about it, I’ll share my private build from source of the SDK.  This comes with a “works on my machine” guarantee :-).  This is a build of SQLite from their source, which is Open Source, and modified to compile/link against the Windows Phone 8.1 SDK.  When the official version comes out you should update to that version from their site.  For now, you can download my build of  UPDATE (12-MAY-2014): SQLite team put out their official build for Windows Phone 8.1: SQLite for Windows Phone 8.1 here.

Updating your Extension SDKs and NuGet packages

If you are an author of one of these SDKs that people use, please consider doing an update to make your customers happy.  If you are an Extension SDK provider you will want to produces an Extension SDK for Windows Phone 8.1.  If you already have a WinRT SDK, then you may just be able to copy the manifest, etc. and just produce changes to your manifest so it installs to the right location.  Here is an example:

<Installation AllUsers="true" Scope="Global">
  <InstallationTarget Id="Microsoft.ExtensionSDK" 
    TargetPlatformIdentifier="WindowsPhoneApp" 
    TargetPlatformVersion="v8.1" 
    SdkName="SQLite.WinRTPhone81" SdkVersion="3.8.4.1" />
</Installation>

As you can see in lines 3,4 above the TPI/V values are different than your existing SDK which tell the SDK where to install.

If you are an author of a NuGet package, you also will want to make your package Windows Phone 8.1 aware.  Again, if you have an existing package that works with Windows 8.1, then you may just be able to duplicate the content/lib/tools to a folder labeled ‘wpa81’ and test that out.  Example NuSpec:

<?xml version="1.0" encoding="utf-8"?>
<package xmlns="http://schemas.microsoft.com/packaging/2010/07/nuspec.xsd">
    <metadata>
        <id>Callisto</id>
        <version>1.5.0</version>
        <title>Callisto</title>
        <authors>Tim Heuer</authors>
        <owners>Tim Heuer</owners>
    </metadata>
    <files>
        <file src="lib\portable-win81+wpa81" target="lib\portable-win81+wpa81" />
    </files>
</package>

If you see at line 11 the ‘portable-win81+wpa81’ it allows me to combine the two targets telling NuGet this applies to either.  Of course if I had any nuanced differences I could also just use ‘wpa81’ and put the phone-specific lib (or assets) there.

In both cases if you have any UI aspects, most likely you may want to do some work here to make sure that any UI assets are tailored to the device targets for a great experience.

I hope this helps clarify some of the reference questions that I’ve received and I hope that if you are an SDK author you will work quickly to help your customers realize their goals of a universal Windows app!

Hope this helps!

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In a previous post I talked about removing the dependency on StandardStyles.xaml from your Windows 8.1 projects.  One of those tips noted that a popular use of the styles in that helper file was the AppBarButton styles and the roughly 200 different glyphs used for AppBarButtons.  I thought I’d dig a little deeper quickly on the use of AppBarButton since I received a few pieces of email about it.

Typical Scenario – Symbol Icons

The AppBarButton class is new in Windows 8.1 and primarily intended for use the CommandBar scenario, providing the UI, behavior and accessibility needs to the control. 

NOTE: CommandBar is new in Windows 8.1 and meant to serve as the best-practices control for AppBars that are non-custom and use only command buttons.  It provides automatic sizing logic (meaning commands will drop as the window gets smaller) built-in as well as better keyboarding support for navigating through the commands in the AppBar.  If you are using AppBar and only have the ‘standard’ button UI, you should be using CommandBar instead in your Windows 8.1 app.

It allows you to rapidly create the UI by setting two properties: Label and Icon.  Here’s a quick example:

<AppBarButton Label="Reply via Email" Icon="MailReply" />

which produces:

Reply via Email icon image

That’s it.  The functionality still remains to be a button and the API surround that type.  This just gives you a quick way to set the label and visual.  All the visual states (pressed/hover/etc) are taken care of for you.  We’ve also pushed through the Label property to be the AutomationProperties.Name value for the button for you, providing accessibility by default here.  This Icon property method is the shortcut version of this more verbose method:

<AppBarButton Label="Reply via Email">
    <AppBarButton.Icon>
        <SymbolIcon Symbol="MailReply" />
    </AppBarButton.Icon>
</AppBarButton>

As you can see the attached property for ButtonBase is where the Icon property lives.  Because we have this Icon property we can use other methods as well.  We also expose an IsCompact property on the AppBarButton types that will shrink the margins and drop the labels automatically for you for a smaller view.  This is what the CommandBar sets when the Window size gets too small to fit the elements.

Using other custom fonts as Icon sources

If one of the 190 included Icon types does not suit your needs you can still use the AppBarButton with your own custom icons.  I HIGHLY recommend using the Font approach as it provides a great automatic scaling method for your icons and seems to be the direction of a lot of apps on the web as well.  While you can make your own Symbol font, there are also many great providers out there that you can use.

NOTE: I am not a lawyer and you should consult the font provider’s license for acceptable use policies/rights/restrictions on using fonts that are embedded in your application.  Don’t assume that every font is acceptable to use in this manner just because it is TTF/OTF – be sure to consult the license if you are not the font author.

Let’s say I want to add some social media commands to my app.  I can use the popular Modern UI Icons library, which happens to provide a font download of the social icons created.  Once unzipped I include the TTF file in my project (I could have used OTF but since TTF is provided I’ll use that – also note I renamed the file in my VS project) and then can use in my app:

<AppBarButton Label="Tweet This">
    <AppBarButton.Icon>
        <FontIcon FontFamily="ms-appx:///modernuiicons.ttf#Modern-UI-Icons---Social" 
            Margin="0,2,0,0" Glyph="&#xe045;" FontSize="37.333" />
    </AppBarButton.Icon>
</AppBarButton>
<AppBarButton Label="Review on Yelp">
    <AppBarButton.Icon>
        <FontIcon FontFamily="ms-appx:///modernuiicons.ttf#Modern-UI-Icons---Social" 
            Margin="0,2,0,0" Glyph="&#xe04f;" FontSize="37.333" />
    </AppBarButton.Icon>
</AppBarButton>

which produces:

Modern UI Icon sample usage

Pretty cool.  Now when using Fonts sometimes it is tricky to figure out the right value to set after the “#” symbol in the FontFamily path.  The trick I use on Windows is to open the TTF/OTF file and it will show the font preview as well as the “Font name” in the very first.  This is the value you want to specify after the path to the actual file.  The Glyph value you supply is totally dependent upon the font you choose.  Most authors use Unicode value ranges for symbols, but I’ve seen some that would be as simple as “B” that you could put there.  This is something you should consult the font provider for a mapping (Modern UI Icons provides a nice web page preview with all the values next to the icons).  Also notice that some font information in the font may vary and you may have to do some adjustments.  For me, I found I had to nudge the Modern UI Icons 2px down as well as size up the FontSize value to my liking.

Other variations of Icon

There are two other variations of Icons you can use.  I recommend using the default Symbol method first as almost always you’ll find something you need in that 190 set.  Second I would recommend looking at the Font approach.  These last two have some caveats that aren’t as “drop in” simple to use usually and greatly depend on the graphic data provided.

  • PathIcon – this is for providing vector data using the XAML Path data format.  This is vector and will scale nicely.  You must, however, provide the vector data already sized to 40px so it fits within the template.  For some this can be difficult if just provided some data.  Using tools like Inkscape or Snycfusion Metro Studio may help.
  • BitmapIcon – this works for providing PNG based images.  Note that these will NOT automatically scale.  You would want to provide the various scale-factor images (100,140,180) for each image provided here.  This can be a cumbersome task and if not done won’t look well on higher resolution displays.  Additionally BitmapIcon doesn’t yield great fidelity for non-rectangular items.

Using Visual Studio

In Visual Studio 2013 some great tooling around this experience was provided so you can easily pick out visuals for your AppBar buttons.  In the property pane for the designer you can see the various properties you can set:

Visual Studio AppBarButton Icon tooling image

There is also tooling for changing to the other types of icons mentioned above as well.

Summary

We wanted to make some things simpler, reduce VS template-provided code and improve app usability/accessibility.  While this feature may seem simple, it is useful and can help you focus on the core of your application rather than some fundamental pieces.  If you are using other button styles and some of the more standard icons, I encourage you to move to AppBarButton with the default Icon types provided by the framework.  Be sure to check out the AppBar Windows SDK Sample for playing around with the concepts discussed in this post.

Hope this helps!

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If you’ve created a Windows 8 app using XAML then you’ve likely seen a file in the project called StandardStyles.xaml in the Common folder and merged in with your application.  As I’ve seen apps developed I’ve seen people pretty much treat this as a system component and not change it at all.  Sometimes that’s good, but mostly it has been bad.  There are a lot of apps that I’ve seen that don’t use a lot of the styles in that dictionary, but don’t do anything to trim the file or even remove it if not needed.

The file was included in Windows 8 Visual Studio project templates to help style some areas of the template.  In looking at performance in Windows 8.1 we saw that people were not removing this file or unused styles in this file.  We also saw that there was benefit to including some of these styles in the framework because of some styles/template deferred loading we implemented in Windows 8.1.  As such for almost all apps we’ve seen in practice, the styles provided in Windows 8/VS2012’s StandardStyles.xaml file can be removed from your application and replaced with styles in the XAML framework.

Text Styles

A big portion of the file is providing some text styles that map to the typographic ramp for the Windows design language.  Roughly 100 lines of text styling can now be migrated to new framework-provided text styles.  Here’s a mapping of what you should examine replacing with in your Windows 8.1 app:

StandardStyles.xaml (in VS 2012)Windows 8.1 XAML Framework-provided name
BasicTextStyleBaseTextBlockStyle
BaselineTextStylen/a (merged with BaseTextBlockStyle)
HeaderTextStyleHeaderTextBlockStyle
SubheaderTextStyleSubheaderTextBlockStyle
TitleTextStyleTitleTextBlockStyle
SubtitleTextStyleSubtitleTextBlockStyle
BodyTextStyleBodyTextBlockStyle
CaptionTextStyleCaptionTextBlockStyle
BaseRichTextStyleBaseRichTextBlockStyle
BaselineRichTextStylen/a (merged with BaseRichTextBlockStyle)
BodyRichTextStyleBodyRichTextBlockStyle
ItemRichTextStylen/a (was same as BodyRichTextBlockStyle)

 

The replacement is pretty simple as wherever you were using {StaticResource SomeTextStyle} you would now change to {StaticResource FrameworkProvidedStyle} (obviously using the correct names).  As with anything, when making these changes test your app to ensure your UI fidelity remains as you expect.  Should you need to continue to style some of the above, you could use these as your BasedOn starting point.

Button Styles

Another area was a series of Button styles around Back button, TextBlock buttons and the most used AppBarButton styles.  TextButtonStyle is now TextBlockButtonStyle and serves as a styled Button for areas like GridView clickable section headers, etc. 

There were also a few Back button styles.  With the introduction of AppBarButton in Windows 8.1, we can provide a better/specific template style provided in the framework with the right glyphs for the arrows.  Instead of using the BackButtonStyle/SnappedBackButtonStyle in StandardStyles.xaml you should use NavigationBackButtonNormalStyle and NavigationBackButtonSmallStyle.  The normal style is the main one that you would use on pages and is the 41x41px standard back button.  The small style is the 30x30px smaller button that you might use for a narrow (formerly snapped) view or other areas.

Perhaps one of the most used areas were the AppBarButton styles.  There is roughly 1100 lines of styling for a series of button styles for the various popular glyphs of AppBar button styles.  We are now providing a typed button that is optimized for that UI and we now have included 190 icon types as a part of the base.  As an example this is what you might have had in your Windows 8 app:

<Button Style="{StaticResource PlayAppBarButtonStyle}" />

And can now be replaced with:

<AppBarButton Icon="Play" Label="Play" />

This reduces the need for the base AppBarButtonStyle as well as the others that were glyph-specific.  If you need them to be RTL specific, just add the FlowDirection property as you need it for your app.  The Label property will map directly through to the AutomationProperties.Name value by default as well for the accessibility needs.

List/Grid Item Templates/Styles

In the Grid/Split templates there were also style item templates for the use in the pages within these templates.  In looking where they were actually used, these were moved to only the pages that need them.  Many people think that your styles/templates must be in App.xaml, but this is not true and most of the time not a good performance decision.  If your style is only used in one page, put it in the resources of that page!  That is what was done with these specific styles for the VS 2013 project templates.  Some were removed in accordance with new guidance around app sizes as well.

Using Visual Studio 2013 for Styling

You may ask yourself now how you would use this or know about them or even remember them!  Luckily Visual Studio 2013 added some great new features in the tools to bring more visibility to these styles.  The resource pane is still there and would show the framework-provided styles as seen here in Blend:

System Resource style selection image

If you are an editor-only person, there is still great news as VS added Style IntelliSense!!!  As you use StaticResource you will get auto-completion on the styles that apply to that style you are on.  For example on TextBlock you will only see Styles that apply to TargetType=TextBlock as seen here:

VS Style IntelliSense image

This IntelliSense will work with your own custom styles as well and is a great productivity enhancement to the tools.  This one of my favorite new features of VS!

If you want to see the details of these styles you can use the great template-editing features in Visual Studio/Blend to inspect them as well.  Once you have the style you can now also F12 (Go to definition) on the Style itself!!!!  This will take you to the definition of the style in the framework’s generic.xaml:

Style Go to definition example

This is an amazing productivity feature that is available for all Styles in XAML, again including your own!  These styles can be manually inspected by looking at the generic.xaml that ships in the Windows SDK (location %programfiles%\Windows Kits\8.1\Include\WinRT\XAML\Design).

Summary

One of our main goals was continue to improve overall app performance for Windows 8.1 for all users.  This optimization of bringing most commonly used styles into the framework benefits developers for consistency and productivity as well as all users for shared use of these templates and reduced load/parse time for each individual app needing to provide some of these core styles.

Hope this helps!

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I’m continuing in my series of helping to provide Callisto migration tips to use new Windows 8.1 features. In a recent post I talked about the Flyout control and provided the path to the platform-provided features. In Callisto, the Menu control was provided as sort of a prescribed content for the Flyout control. In fact you really couldn’t use Menu without Flyout.

Menu control sample image

This guide will help you change to the platform-provided MenuFlyout now available in Windows 8.1.

API Differences

On the public surface area, there aren’t actually many changes here. Windows 8.1 MenuFlyout provides more functionality as it derives from FlyoutBase, which is the base for Flyout as well. So you get the same ShowAttachedFlyout capability that you have there. Both have an Items property that is a collection of the menu items you’d put in there. For these purposes I’m not detailing out the minutiae of differences between FlyoutBase and Menu here as it isn’t relevant to migration but is useful later as I’ll demonstrate. The main reason is that as I noted earlier, you actually can’t use Menu in Callisto without using Flyout, hence the lack of a significant delta here at the Menu level.

Change to the MenuFlyout

As with the other examples, I’m going to use the Callisto test app code here to show migration. Since Menu needed Flyout, you had more of a code-focused approach in ideal Callisto usage. We believe that the main use cases for Menus are also in Button invoke scenarios. Here’s an example of showing a Menu in Callisto:

private void ShowFlyoutMenu(object sender, RoutedEventArgs e)
{
    Callisto.Controls.Flyout f = new Callisto.Controls.Flyout();
    f.PlacementTarget = sender as UIElement;
    f.Placement = PlacementMode.Top;
    f.Closed += (x, y) =>
    {
        LogEvent("Event: Closed");
    };
 
    Menu menu = new Menu();
 
    MenuItem mi = new MenuItem();
    mi.Tag = "Easy";
    mi.Tapped += ItemClicked;
    mi.Text = "Easy Game";
    mi.MenuTextMargin = new Thickness(28, 10, 28, 12);
 
    MenuItem mi2 = new MenuItem();
    mi2.Text = "Medium Game";
    mi2.Tag = "Medium";
    mi2.Tapped += ItemClicked;
    mi2.MenuTextMargin = new Thickness(28, 10, 28, 12);
 
    ToggleMenuItem tmi = new ToggleMenuItem();
    tmi.Text = "Enable Logging";
    tmi.IsChecked = chk;
    tmi.Tapped += (a, b) =>
        {
            chk = !chk;
        };
 
    menu.Items.Add(mi);
    menu.Items.Add(mi2);
    menu.Items.Add(new MenuItemSeparator());
    menu.Items.Add(new MenuItem() { Text = "Foobar something really long", Tag = "Long menu option", MenuTextMargin = new Thickness(28,10,28,12) });
    menu.Items.Add(tmi);
 
    f.HostMargin = new Thickness(0); // on menu flyouts set HostMargin to 0
    f.Content = menu;
    f.IsOpen = true;
}

You will have to understand some of the events and variables are examples here (LogEvent and chk). Notice how you have to create a Flyout first, then put the Menu in it with all the items. Here is how you would migrate that code to provide immediate migration to the platform control:

private void ShowMenuFlyout3(object sender, RoutedEventArgs e)
{
    MenuFlyout mf = new MenuFlyout();
    MenuFlyout.SetAttachedFlyout(sender as FrameworkElement, mf);
    mf.Closed += (x, y) =>
        {
            LogEvent("Event: Closed");
        };
 
    MenuFlyoutItem mi = new MenuFlyoutItem();
    mi.Tag = "Easy";
    mi.Tapped += ItemClicked;
    mi.Text = "Easy Game";
 
    MenuFlyoutItem mi2 = new MenuFlyoutItem();
    mi2.Text = "Medium Game";
    mi2.Tag = "Medium";
    mi2.Tapped += ItemClicked;
 
    ToggleMenuFlyoutItem tmi = new ToggleMenuFlyoutItem();
    tmi.Text = "Enable Logging";
    tmi.IsChecked = chk;
    tmi.Tapped += (a, b) =>
        {
            chk = !chk;
        };
 
    mf.Items.Add(mi);
    mf.Items.Add(mi2);
    mf.Items.Add(new MenuFlyoutSeparator());
    mf.Items.Add(tmi);
 
    MenuFlyout.ShowAttachedFlyout(sender as FrameworkElement);
}

Now notice how the shape of the items is similar so helping with some migration. You create a MenuFlyout, MenuFlyoutItems (notice the separator and ToggleMenuFlyoutItem), then add them to the MenuFlyout and show it. But just like Flyout in Windows 8.1 we believe there was an easier way we could provide creating and using MenuFlyout.

A better way to use MenuFlyout

Much like Flyout we believe the primary use case for MenuFlyout will be from ButtonBase invocations. Let’s look at the declarative approach to the code above:

<AppBarButton Icon="Add" Label="New Game">
     <AppBarButton.Flyout>
         <MenuFlyout>
             <MenuFlyoutItem Tag="Easy" Text="Easy Game" Tapped="ItemClicked" />
             <MenuFlyoutItem Tag="Medium" Text="Medium Game" Tapped="ItemClicked" />
             <MenuFlyoutSeparator />
             <ToggleMenuFlyoutItem Text="Enable Logging" IsChecked="True" />
         </MenuFlyout>
     </AppBarButton.Flyout>
 </AppBarButton>

This allows us to provide an automatic way to show the menu when the button is clicked. If we aren’t using a Button we can still use the Set/ShowAttachedFlyout method as demonstrated above.

Summary

Moving to the new MenuFlyout control will again gain you better performance, compliance with UI guidelines, declarative model and accessibility features. As you can see there is a short-term migration approach using the the ShowAttachedFlyout method to allow you to very quickly take advantage of the new control if you were using the Callisto code method. Your app can then decide if it makes sense to move to the declarative model. Either way, the new control is great and you should use it! We also have a Windows 8.1 MenuFlyout SDK Sample that you can examine to play around with the API.

Hope this helps!

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This is another post in my series of providing migration tips from certain Callisto controls to using Windows 8.1 features. I previously demonstrated probably the most popular Callisto control, the SettingsFlyout. Coming in a very close second in popularity is the Flyout control. The Flyout is a concept of a non-modal small dialog for information and commands.

Flyout sample image

The primary use case for a lot of Flyouts was something from Button areas, namely the AppBar. Getting the experience right was not intuitively easy using a Popup primitive as you had to handle the right UI guidelines for animation, positioning and dismiss logic. Callisto provided most of this in the Flyout class but also left some people wanting a bit more flexibility. This post will aim to help you migrate existing Callisto Flyout code to the new Windows 8.1 Flyout class.

API Differences

As I did with showing some of the more prominent API differences in SettingsFlyout, I’m presenting some of the important differences for Flyout here. You should read this table as Callisto API==old, Windows 8.1 API==new and what you should use.

Callisto APIWindows 8.1 APIComments
HorizontalOffset/VerticalOffsetn/aNot really needed in almost all default cases. If you really needed to adjust the default logic, you could provide a template for FlyoutPresenter and change the margin there.
HostMarginn/aNot needed
HostPopupn/aNot needed
IsOpenShowAttachedFlyoutSee explanation below
PlacementPlacementSame concept, different enum
PlacementTargetShowAttachedFlyoutSee explanation below
ClosedClosed
n/aOpenedNew event
n/aOpeningNew event

Changing your code – an example

Similar to previous examples, I’m going to use the Callisto test app examples here. Flyout in Callisto was another control that didn’t work well in markup. This section will show how you would change your existing code if you were using the Callisto method to use the new Flyout in Windows 8.1. After this section I’ll explain a better way to do this for most cases and the preferred way to use the control. However again I want to provide a “least code change” mechanism to migrate and will do so here.

In Callisto, you most likely wrote code to trigger opening a Flyout. Here’s an example taken from the test app (this was from a Button click event):

private void ShowFlyoutMenu2(object sender, RoutedEventArgs e)
{
    Callisto.Controls.Flyout f = new Callisto.Controls.Flyout();
 
    // content code removed for brevity
    // assume "b" variable here represents a visual tree or a user control
    f.Content = b;
 
    f.Placement = PlacementMode.Top;
    f.PlacementTarget = sender as UIElement;
    
    f.IsOpen = true;
}

The code here basically requires you to wire this up in an event handler and provide the UIElement as the PlacementTarget so it knows where to position the Flyout.

To change this here is what it would look like in Windows 8.1:

private void ShowFlyoutMenu2(object sender, RoutedEventArgs e)
{
    Flyout f = new Flyout();
 
    // again for brevity sake assume "b" here represents content
    f.Content = b;
 
    Flyout.SetAttachedFlyout(sender as FrameworkElement, f);
    Flyout.ShowAttachedFlyout(sender as FrameworkElement);
}

The key here is the SetAttachedFlyout/ShowAttachedFlyout method calls. You must first attach the Flyout to the FrameworkElement (again in this case this is on a Button). Then you show it. I’ve omitted the Placement here to allow for the new default (top) to occur. You could have also added Placement to the change as well. Placement will attempt to fit in this order: Top, Bottom, Left, Right.

The above is meant to demonstrate how to quickly change from Callisto code with minimal impact. The next section actually shows a preferred way of using the control and what a lot of Callisto users were actually asking for.

A better way to use Flyout

As demonstrated the Flyout can still be called from code after attaching it to a FrameworkElement. You are then responsible for calling the ShowAttachedFlyout method to open it. The Windows 8.1 Flyout was designed for the primary use case of ButtonBase elements and will automatically show for you when used in those cases. Let’s assume an example where I have a Button in my AppBar (btw, you should use the new AppBarButtons in Windows 8.1) and I want to show a Flyout when the user clicks on the button. I could do the event model above, but my MVVM friends are cringing a bit. Here’s an alternate and the most likely way you would use Flyout:

<AppBarButton Icon="Add" Label="Add File">
    <AppBarButton.Flyout>
        <Flyout>
            <!-- content here -->
        </Flyout>
    </AppBarButton.Flyout>
</AppBarButton>

As you can see here, on Button we’ve provided an attached property to put the Flyout element and its content. The framework will handle the showing of the Flyout when automatically attached to the Button like this. If you don’t want to use the Button method and perhaps you have to launch a Flyout from some other UIElement, you would use the ShowAttachedFlyout method as demonstrated above.

Summary

As one of the more popular controls this migration may take you down the quick route first and then give you more time to think about using the declarative way to really change later. I recommend using the new Flyout here as you will get all the proper behavior as well as better performance, accessibility and interaction with the software keyboard. We also have a new Windows 8.1 Flyout SDK Sample that walks through this usage and some other scenarios you can examine for your needs.

Hope this helps!