Xamarin.Forms 1.5.2.6469-pre1

Build native UIs for iOS, Android, and Windows Phone from a single, shared C# codebase

This is a prerelease version of Xamarin.Forms.
There is a newer version of this package available.
See the version list below for details.
Install-Package Xamarin.Forms -Version 1.5.2.6469-pre1
dotnet add package Xamarin.Forms --version 1.5.2.6469-pre1
<PackageReference Include="Xamarin.Forms" Version="1.5.2.6469-pre1" />
For projects that support PackageReference, copy this XML node into the project file to reference the package.
paket add Xamarin.Forms --version 1.5.2.6469-pre1
The NuGet Team does not provide support for this client. Please contact its maintainers for support.

Release Notes

## Important Notes ##

This release is more alpha than most pre-releases. We want to get as much testing on the new optimization work as possible. Expect to see changes and more work landing into this release before promotion to stable.

## Enhancements ##

### New properties ###

These all do pretty much what you expect

- Editor.TextColor
- Entry.TextColor
- Editor.FontSize
- Editor.FontAttributes
- Editor.FontFamily

### New API ###

```csharp
public enum ListViewCachingStrategy
{
RetainElement = 0,
RecycleElement,
}
```

This new `enum` is used in conjuction with a new constructor for ListView, `ListView (ListViewCachingStrategy cachingStrategy)`. The default mode, RetainElement represents the old ListView behavior. It is also the default behavior if the old constructor is retained. The new behavior has the following characteristics.

- Only works on Android/iOS. Windows will simply get the old behavior no matter what.
- DataTemplate will be inflated to match as many native renderers for the cells are created.
- During virtualization, the Cell will have its binding context updated.

This means if an App opt into the new mode, the app must appropriately handle BindingContext updates. All data about the cell must come from the binding context or consistency errors may occur. If the cells are using custom renderers, it must ensure they properly implement property change notification. This mode is not always a pure performance win, testing is the only way to know for sure, however there are some basic guidelines:

 - Use RecycleElement if:
   - Cell BindingContext defines all properties/data about the View
   - Cells are largely similar and do not morphe dramatically based on BindingContext
   - The Cell has a moderate to small number of bindings
   - The Cell adheres well to the new performance guidelines below
 - Use RetainElement if:
   - Cells morph frequently
   - Cells have large numbers of bindings (20 to 30 tends to be the crossover point)
   - When testing RecycleElement, it is slower

Generally speaking, prefer RecycleElement as it can offer significant performance gains when in the fast path scenario. Eventually RetainElement may be phased out, however this will only happen once RetainElement no longer offers any performance advantage in any scenario.

### Layout Optimization ###

There is a new experimental layout optimization in this release of Xamarin.Forms. The optimization is complex and currently only impacts layout updates. Effectively the optimization serves to block InvalidateMeasure call chains. To get the best possible performance follow these performance guidelines:

- Leave the View.VerticalOptions and View.HorizontalOptions alone as much as possible. The default value of Fill or FillAndExpand allows for the best layout optimization.
- When using a StackLayout, make sure to have only one child set to Expand.
- Avoid RelativeLayout when possible.
- When using Grid, avoid Auto rows/columns if possible. Fixed row/cols are best. Stars are equally good if parent tree follows guidelines.
- When using AbsoluteLayout, avoid using AutoSize if possible.
- When using Labels, set the LineBreakMode to NoWrap whenever possible.

This optimization may impact the layout of your app. If you experience any differences at all, please report them as bugs. Further the optimization will work with the new ListView caching strategy, effectively doubling down on scrolling performance.

## Bug Fixes ##

[Bug 34632](https://bugzilla.xamarin.com/show_bug.cgi?id=34632) - Can't change IsPresented when setting SplitOnLandscape
[Bug 34556](https://bugzilla.xamarin.com/show_bug.cgi?id=34556) - Minimum version determination methods on iOS will fail once iOS hits version 10
[Bug 34549](https://bugzilla.xamarin.com/show_bug.cgi?id=34549) - Setting a BindableProperty of Type DateTime? to null raises Error
[Bug 34235](https://bugzilla.xamarin.com/show_bug.cgi?id=34235) - Xamarin.Forms.Platform.WinRT.TabbedPageRenderer OnElementChanged not virtual
[Bug 34061](https://bugzilla.xamarin.com/show_bug.cgi?id=34061) - RelativeLayout - First child added after page display does not appear
[Bug 34007](https://bugzilla.xamarin.com/show_bug.cgi?id=34007) - Z order drawing of children views are different on Android and iOS
[Bug 33764](https://bugzilla.xamarin.com/show_bug.cgi?id=33764) - Frame outline colour doesn't change using ViewModel
[Bug 33612](https://bugzilla.xamarin.com/show_bug.cgi?id=33612) - Removing a page from the navigation stack causes an 'Object reference' exception in Android only
[Bug 33499](https://bugzilla.xamarin.com/show_bug.cgi?id=33499) - Android WebViewRenderer doesn't unhook events properly
[Bug 32902](https://bugzilla.xamarin.com/show_bug.cgi?id=32902) - [iOS | iPad] App Crashes (without debug log) when Master Detail isPresented and navigation being popped
[Bug 32801](https://bugzilla.xamarin.com/show_bug.cgi?id=32801) - Memory Leak in TabbedPage + NavigationPage
[Bug 32447](https://bugzilla.xamarin.com/show_bug.cgi?id=32447) - [iOS] App crash when scrolling quickly through a TableView that has Pickers in the cells.
[Bug 32040](https://bugzilla.xamarin.com/show_bug.cgi?id=32040) - EntryCell.Tapped or SwitchCell.Tapped does not fire when within a TableView
[Bug 31366](https://bugzilla.xamarin.com/show_bug.cgi?id=31366) - Pushing and then popping a page modally cause ArgumentOutOfRangeException
[Bug 29257](https://bugzilla.xamarin.com/show_bug.cgi?id=29257) - CarouselPage.CurrentPage Does Not Work Properly When Used Inside a NavigationPage

## Other Fixes ##

- [A] Non-AppCompat backend no longer fails to redraw Frame correctly
- OnPlatform now passing the Windows value to WinRT projects. This API is being considered for replacement with something more extensible.
- OpenGLView now uses IOpenGLViewController for backend communication

Showing the top 10 GitHub repositories that depend on Xamarin.Forms:

Repository Stars
dotnet-architecture/eShopOnContainers
Easy to get started sample reference microservice and container based application. Cross-platform on Linux and Windows Docker Containers, powered by .NET Core 2.2, Docker engine and optionally Azure, Kubernetes or Service Fabric. Supports Visual Studio, VS for Mac and CLI based environments with Docker CLI, dotnet CLI, VS Code or any other code editor.
microsoft/ailab
Experience, Learn and Code the latest breakthrough innovations with Microsoft AI
reactiveui/ReactiveUI
An advanced, composable, functional reactive model-view-viewmodel framework for all .NET platforms that is inspired by functional reactive programming. ReactiveUI allows you to abstract mutable state away from your user interfaces, express the idea around a feature in one readable place and improve the testability of your application.
PrismLibrary/Prism
Prism is a framework for building loosely coupled, maintainable, and testable XAML applications in WPF, Windows 10 UWP, and Xamarin Forms.
xamarin/xamarin-forms-samples
Sample apps built using the Xamarin.Forms framework
MvvmCross/MvvmCross
The .NET MVVM framework for cross-platform solutions, including Xamarin.iOS, Xamarin.Android, Windows and Mac.
mono/monodevelop
MonoDevelop is a cross platform .NET IDE
Caliburn-Micro/Caliburn.Micro
A small, yet powerful framework, designed for building applications across all XAML platforms. Its strong support for MV* patterns will enable you to build your solution quickly, without the need to sacrifice code quality or testability.
reactiveui/Akavache
An asynchronous, persistent key-value store created for writing desktop and mobile applications, based on SQLite3. Akavache is great for both storing important data as well as cached local data that expires.
xamarin/XamarinComponents
Plugins for Xamarin

Version History

Version Downloads Last updated
4.3.0.851321-pre3 5,071 10/2/2019
4.3.0.819712-pre2 6,164 9/19/2019
4.3.0.778476-pre1 6,097 9/11/2019
4.2.0.848062 41,067 10/2/2019
4.2.0.815419 46,108 9/19/2019
4.2.0.778463 40,560 9/11/2019
4.2.0.709249 87,124 8/21/2019
4.2.0.673161-pre3 6,782 8/7/2019
4.2.0.618605-pre2 8,162 7/24/2019
4.2.0.608146-pre1 3,519 7/16/2019
4.1.0.778454 6,919 9/11/2019
4.1.0.709244 18,564 8/21/2019
4.1.0.673156 76,436 8/7/2019
4.1.0.618606 78,567 7/24/2019
4.1.0.581479 91,402 7/9/2019
4.1.0.555618 152,913 6/28/2019
4.1.0.496342-pre2 7,102 6/13/2019
4.1.0.483098-pre1 4,757 6/5/2019
4.0.0.709238 1,786 8/21/2019
4.0.0.618610 2,226 7/24/2019
4.0.0.540366 31,268 6/27/2019
4.0.0.497661 63,559 6/13/2019
4.0.0.482894 50,056 6/3/2019
4.0.0.425677 180,728 5/14/2019
4.0.0.394984-pre10 9,394 5/3/2019
4.0.0.346134-pre9 15,804 4/18/2019
4.0.0.304370-pre8 11,008 4/3/2019
4.0.0.250467-pre7 7,624 3/20/2019
4.0.0.232914-pre6 8,526 3/14/2019
4.0.0.169046-pre5 6,024 2/21/2019
4.0.0.135214-pre4 4,733 2/6/2019
4.0.0.94569-pre3 4,348 1/24/2019
4.0.0.62955-pre2 13,576 1/10/2019
4.0.0.8055-pre1 13,853 12/4/2018
3.6.0.709228 7,570 8/21/2019
3.6.0.539721 23,498 6/27/2019
3.6.0.344457 173,918 4/18/2019
3.6.0.293080 96,442 4/3/2019
3.6.0.264807 165,946 3/19/2019
3.6.0.220655 109,166 3/6/2019
3.6.0.169048-pre2 550 2/21/2019
3.6.0.135200-pre1 4,979 2/6/2019
3.5.0.274416 16,710 3/26/2019
3.5.0.169047 92,901 2/20/2019
3.5.0.129452 138,482 2/6/2019
3.5.0.94564-pre3 1,129 1/24/2019
3.5.0.62956-pre2 1,057 1/10/2019
3.4.0.1039999 13,421 3/26/2019
3.4.0.1029999 91,315 1/24/2019
3.4.0.1009999 108,286 1/4/2019
3.4.0.1008975 466,122 11/15/2018
3.4.0.987044-pre2 2,378 11/8/2018
3.4.0.925479-pre1 11,177 10/18/2018
3.3.0.967583 170,379 11/1/2018
3.3.0.912540 125,181 10/18/2018
3.3.0.893527-pre3 8,029 10/11/2018
3.3.0.871608-pre2 12,290 10/1/2018
3.3.0.840541-pre1 6,299 9/20/2018
3.2.0.871581 117,374 10/3/2018
3.2.0.839982 166,167 9/17/2018
3.2.0.809874-pre3 3,865 9/10/2018
3.2.0.729530-pre2 13,198 8/14/2018
3.2.0.637442-pre1 10,960 7/17/2018
3.1.0.697729 360,777 8/1/2018
3.1.0.637273 109,470 7/11/2018
3.1.0.583944 151,144 6/20/2018
3.1.0.561732-pre4 6,442 6/11/2018
3.1.0.550168-pre3 3,120 6/6/2018
3.1.0.530888-pre2 1,944 6/4/2018
3.1.0.469394-pre1 11,517 5/9/2018
3.0.0.561731 147,490 6/11/2018
3.0.0.550146 28,281 6/6/2018
3.0.0.530893 21,813 6/4/2018
3.0.0.482510 254,631 5/14/2018
3.0.0.446417 137,746 5/1/2018
3.0.0.427558-pre4 9,385 4/25/2018
3.0.0.354232-pre3 14,315 4/5/2018
3.0.0.296286-pre2 8,439 3/20/2018
2.5.1.527436 94,372 5/4/2018
2.5.1.444934 173,435 4/4/2018
2.5.1.392594-pre3 4,309 3/21/2018
2.5.1.340284-pre2 6,569 3/9/2018
2.5.1.317207-pre1 5,810 3/1/2018
2.5.0.280555 329,199 2/16/2018
2.5.0.122203 341,016 12/18/2017
2.5.0.121934 222,665 11/28/2017
2.5.0.91635 166,586 11/16/2017
2.5.0.77107 30,958 11/13/2017
2.5.0.75255-pre3 5,577 11/10/2017
2.5.0.19271-pre2 9,583 10/20/2017
2.4.0.91020 50,142 11/16/2017
2.4.0.74863 35,291 11/10/2017
2.4.0.38779 62,223 10/30/2017
2.4.0.18342 56,315 10/20/2017
2.4.0.282 164,931 9/29/2017
2.4.0.280 206,951 9/27/2017
2.4.0.275-pre3 8,260 9/19/2017
2.4.0.269-pre2 13,881 8/29/2017
2.4.0.266-pre1 20,102 8/16/2017
2.3.5.256-pre6 36,295 6/29/2017
2.3.5.255-pre5 5,054 6/26/2017
2.3.5.239-pre3 28,334 5/11/2017
2.3.5.235-pre2 11,454 4/26/2017
2.3.5.233-pre1 9,323 4/13/2017
2.3.4.270 154,823 8/29/2017
2.3.4.267 68,936 8/16/2017
2.3.4.247 426,817 5/16/2017
2.3.4.231 214,376 4/12/2017
2.3.4.224 252,226 3/29/2017
2.3.4.221-pre6 7,589 3/27/2017
2.3.4.214-pre5 10,481 3/14/2017
2.3.4.212-pre4 6,410 3/10/2017
2.3.4.211-pre3 4,345 3/9/2017
2.3.4.192-pre2 19,624 2/3/2017
2.3.4.184-pre1 13,178 1/13/2017
2.3.3.193 249,405 2/1/2017
2.3.3.180 212,431 1/5/2017
2.3.3.175 118,849 12/6/2016
2.3.3.168 67,269 11/23/2016
2.3.3.166-pre4 8,230 11/3/2016
2.3.3.163-pre3 6,556 10/17/2016
2.3.3.152-pre2 16,284 9/15/2016
2.3.2.127 293,181 9/14/2016
2.3.2.118-pre1 6,967 8/3/2016
2.3.1.114 157,036 8/3/2016
2.3.1.113-pre3 3,972 7/19/2016
2.3.1.111-pre2 4,907 7/4/2016
2.3.1.110-pre1 2,624 6/29/2016
2.3.0.107 208,047 6/29/2016
2.3.0.49 89,205 6/16/2016
2.3.0.46-pre3 16,317 5/30/2016
2.3.0.38-pre2 13,379 4/27/2016
2.3.0.34-pre1 8,950 4/27/2016
2.2.0.45 139,365 5/30/2016
2.2.0.31 128,630 4/27/2016
2.2.0.23-pre4 3,247 4/20/2016
2.2.0.18-pre3 2,461 4/20/2016
2.2.0.5-pre2 16,156 4/8/2016
2.2.0.4-pre1 18,671 4/5/2016
2.1.0.6529 99,167 3/13/2016
2.1.0.6526 17,772 3/9/2016
2.1.0.6524 36,883 3/2/2016
2.1.0.6521 12,304 3/1/2016
2.1.0.6517-pre5 2,340 2/18/2016
2.1.0.6513-pre4 2,322 2/9/2016
2.1.0.6508-pre3 2,638 1/28/2016
2.1.0.6503-pre2 7,225 1/22/2016
2.1.0.6501-pre1 1,778 1/21/2016
2.1.0.6500-pre1 1,604 1/20/2016
2.0.1.6505 93,973 1/28/2016
2.0.1.6495 75,464 1/20/2016
2.0.1.6492-pre1 4,061 12/3/2015
2.0.0.6490 98,714 12/1/2015
2.0.0.6484 18,025 11/21/2015
2.0.0.6482 242,856 11/17/2015
1.5.2.6478-pre3 1,482 11/17/2015
1.5.2.6477-pre2 4,122 11/10/2015
1.5.2.6469-pre1 2,409 10/20/2015
1.5.1.6471 77,360 10/20/2015
1.5.1.6468 4,132 10/20/2015
1.5.1.6460-pre2 1,875 10/13/2015
1.5.1.6455-pre1 3,234 10/2/2015
1.5.0.6447 56,404 9/25/2015
1.5.0.6446 22,019 9/16/2015
1.5.0.6404-pre3 3,524 8/25/2015
1.5.0.6401-pre2 1,726 8/21/2015
1.5.0.6396-pre1 2,163 8/5/2015
1.4.4.6449 2,973 9/25/2015
1.4.4.6443 1,872 9/16/2015
1.4.4.6392 77,796 7/29/2015
1.4.4.6391 2,218 7/28/2015
1.4.4.6387 3,155 7/27/2015
1.4.4.6379-pre3 1,745 7/20/2015
1.4.4.6378-pre2 1,566 7/16/2015
1.4.4.6377-pre1 1,572 7/14/2015
1.4.3.6376 43,049 7/9/2015
1.4.3.6374 16,885 7/1/2015
1.4.3.6372 2,298 6/30/2015
1.4.3.6364-pre3 2,545 6/16/2015
1.4.3.6358-pre2 5,986 4/24/2015
1.4.3.6356-pre1 1,656 4/21/2015
1.4.2.6359 63,527 4/30/2015
1.4.2.6355 14,680 4/21/2015
1.4.2.6353-pre2 2,710 3/31/2015
1.4.2.6350-pre1 1,761 3/30/2015
1.4.1.6349 44,880 3/30/2015
1.4.1.6347-pre2 3,444 3/19/2015
1.4.1.6342-pre1 1,898 3/10/2015
1.4.0.6341 29,299 3/9/2015
1.4.0.6340-pre2 2,746 3/6/2015
1.4.0.6336-pre1 1,730 3/3/2015
1.3.5.6337 5,332 3/5/2015
1.3.5.6335 25,631 3/2/2015
1.3.5.6333-pre1 2,307 2/17/2015
1.3.4.6332 19,545 2/17/2015
1.3.4.6331-pre4 1,762 2/13/2015
1.3.4.6329-pre3 1,489 2/12/2015
1.3.4.6328-pre2 1,496 2/11/2015
1.3.4.6325-pre1 1,461 2/9/2015
1.3.3.6323 53,591 2/9/2015
1.3.3.6322-pre3 1,460 2/6/2015
1.3.3.6321-pre2 1,621 2/4/2015
1.3.3.6318-pre1 1,617 2/2/2015
1.3.2.6316 7,985 2/3/2015
1.3.2.6313-pre3 1,606 1/30/2015
1.3.2.6309-pre2 1,653 1/28/2015
1.3.2.6299-pre1 2,363 1/20/2015
1.3.1.6296 57,527 1/4/2015
1.3.1.6294-pre1 4,692 12/24/2014
1.3.0.6292 9,841 12/24/2014
1.3.0.6286-pre4 2,362 12/19/2014
1.3.0.6284-pre3 1,864 12/12/2014
1.3.0.6280-pre2 1,819 12/9/2014
1.3.0.6275-pre1 8,092 11/12/2014
1.2.3.6257 39,499 10/2/2014
1.2.3.6256-pre4 2,502 9/26/2014
1.2.3.6255-pre3 2,910 9/20/2014
1.2.3.6249-pre2 2,087 9/9/2014
1.2.3.6246-pre1 4,663 8/15/2014
1.2.2.6243 29,050 7/30/2014
1.2.2.6241-pre3 3,020 7/28/2014
1.2.2.6240-pre2 4,857 7/22/2014
1.2.2.6238-pre1 4,019 7/17/2014
1.2.1.6229 8,830 7/14/2014
1.1.1.6206 14,470 6/19/2014
1.1.0.6201 13,900 6/12/2014
1.0.6197 4,537 6/4/2014
1.0.6188 12,046 5/28/2014
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