Bug 32988 - [XF 1.4.4] Modifying XAML files causes IntelliSense for references to other PCLs to fail in the ".xaml.cs" codebehind files with errors of the form "are you missing an assembly reference?"
Summary: [XF 1.4.4] Modifying XAML files causes IntelliSense for references to other P...
Alias: None
Product: Forms
Classification: Xamarin
Component: Forms ()
Version: unspecified
Hardware: PC Windows
: Normal normal
Target Milestone: ---
Assignee: Bugzilla
: 36657 37413 ()
Depends on: 33181
Blocks: 39827
  Show dependency tree
Reported: 2015-08-11 23:34 UTC by Brendan Zagaeski (Xamarin Team, assistant)
Modified: 2016-04-15 15:47 UTC (History)
25 users (show)

Tags: BZRXF1.4.4.6392_1.4.3.6376 , _XVS1215
Is this bug a regression?: ---
Last known good build:

Test case (269.39 KB, application/zip)
2015-08-11 23:34 UTC, Brendan Zagaeski (Xamarin Team, assistant)
Zip Xamarin Logs (1018.22 KB, application/octet-stream)
2015-08-12 09:24 UTC, Udham Singh

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Description Brendan Zagaeski (Xamarin Team, assistant) 2015-08-11 23:34:11 UTC
Created attachment 12462 [details]
Test case

[XF 1.4.4] Modifying XAML files causes IntelliSense for references to other PCLs to fail in the ".xaml.cs" codebeind files with errors of the form "are you missing an assembly reference?"

## Regression status: regression between 1.4.3 and 1.4.4


My guess would be that this is a side-effect of the new `.g.cs` generator logic and therefore closely related to the fix for Bug 32341.

## About the test case

This is a new app created from scratch to imitate the setup of one of the XAML pages in the "XLabs.Sample" project from the XLabs repo [1].

> [1] https://github.com/XLabs/Xamarin-Forms-Labs

## Steps to reproduce

1. Open the attached test case.

2. Restore the NuGet packages.

3. Make a modification to the `Page1.xaml` file and save it. It is sufficient
just to overwrite "Page1" with "Page1" and save the file.

4. Navigate to the `Page1.xaml.cs` file to check the IntelliSense status of the "BaseView" type and the "XLabs.Forms" namespace.

## Results

The "BaseView" type and the "XLabs.Forms" names cannot be found.

### Error messages from "View -> Error List"

> The type or namespace name 'Forms' does not exist in the namespace 'XLabs' (are you missing an assembly reference?)
> The type or namespace name 'BaseView' could not be found (are you missing a using directive or an assembly reference?)

## Additional notes

- If you remove the `MSBuild:UpdateDesignTimeXaml` "Custom Tool" on "Page1.xaml", clean the project, and then close and reopen the solution, the "BaseView" and "XLabs.Forms" names _will_ be found.

- Building the project succeeds without error. It is only the IntelliSense that produces these "false" error messages.

- The problem only affects Visual Studio. It does not affect Xamarin Studio on Windows.

## Additional version info (brief)

### Windows 8.1 (64-bit) in VMWare Fusion 6.0.6

Microsoft Visual Studio Professional 2013
Version 12.0.40629.00 Update 5
Microsoft .NET Framework
Version 4.6.00081

Xamarin   3.11.836.0 (ed5c750)
Comment 1 Udham Singh 2015-08-12 09:24:35 UTC
Created attachment 12472 [details]
Zip Xamarin Logs

I have checked this issue with the help of test steps given in bug description and able to reproduce the reported behavior.

Screencast : http://www.screencast.com/t/FEtsBHA8hn

Environment Info : 


Microsoft Visual Studio Professional 2013
Version 12.0.31101.00 Update 4
Microsoft .NET Framework
Version 4.5.50938

Installed Version: Professional

Xamarin   3.11.868.0 (d98cdcb)
Comment 4 Brock Holum 2015-10-26 10:10:33 UTC
Are there any updates on this issue? We have a project with a large number of screens built in XAML and can't upgrade past because of it. We also can't work in Xamarin Studio due to C#6 features that aren't implemented yet.

Xamarin.Forms >
Microsoft Visual Studio Professional 2015
Version 14.0.23107.0D14REL
Microsoft .NET Framework
Version 4.6.00081
Xamarin 3.11.1537.0 (a11147b)
Comment 6 Jason Michas 2015-12-07 23:36:41 UTC
I can't believe this has been a known issue for 4 months and has not been fixed. I understand that it is not an impediment to building but for those of us who live (and BTW, pay extra to use Xamarin in VS) this is a huge problem.

I live in VS all day and this is just a thorn in my side and really is starting to make coding anything with slightly complex architectures annoying as hell.
Comment 8 Brendan Zagaeski (Xamarin Team, assistant) 2015-12-15 00:55:37 UTC
## Possible partial workaround for VS 2015 Update 1 users

For any users running VS 2015 Update 1, there is a chance that switching to using VS 2015 Update 1's built-in Xamarin.Forms IntelliSense [1] might help.

[1] https://visualstudiogallery.msdn.microsoft.com/8195a8e2-a842-4389-a8cb-34e4672e2e13
Comment 9 Brendan Zagaeski (Xamarin Team, assistant) 2015-12-15 00:56:33 UTC
*** Bug 36657 has been marked as a duplicate of this bug. ***
Comment 10 Brendan Zagaeski (Xamarin Team, assistant) 2016-01-06 03:29:00 UTC
*** Bug 37413 has been marked as a duplicate of this bug. ***
Comment 11 Jason Michas 2016-01-16 21:07:24 UTC
Is there any info on this bug? Its been 5 months+ now and the posted work around does nothing especially for those of us who use Resharper, which I would assume is a large portion of the user group. 

I even tried disabling Resharper because I find it nearly impossible to work since my projects have many assemblies that are used in xaml markup for extensions, controls, converters, etc. Every time I make a xaml change and save it, so much of my editor page goes red with errors its almost impossible to keep working without doing a clean and rebuild. Clean and rebuild takes a long time and slows all work down. I think the importance of this bug should be escalated to something more than "normal".
Comment 12 Victor Arce 2016-02-04 01:47:48 UTC
@Jason Michas  I totally agree with you, this is a pain in the butt.
Comment 13 Brendan Zagaeski (Xamarin Team, assistant) 2016-02-04 01:53:50 UTC
Just for cross-referencing, I'll record that there is a small status update on the investigation for this issue in the bug that this bug "depends on":

Bug 33181, Comment 26

To summarize briefly, the engineers have started digging into the issue.
Comment 15 Brendan Zagaeski (Xamarin Team, assistant) 2016-03-09 03:46:41 UTC
## Verification status: not yet fixed on the latest published versions

BAD: XF + XamarinVS (a9dd59b)
BAD: XF + XamarinVS (a9dd59b)

Tested on both Visual Studio 2013 Update 3 and Visual Studio 2015 Update 1.

I first tested with the original steps from Comment 0. That still showed the original problem. Then I tried creating a new solution from scratch. That also showed the problem.

## Steps followed to replicate "from scratch"

1. Create a new "Visual C# -> Cross-Platform -> Blank App (Xamarin.Forms Portable)" app named "FormsPortable1".

2. Add a "Visual C# -> Cross-Platform -> Class Library (Xamarin.Forms)" library named "PortableClassLibrary1" to the solution.

3. Add a reference to "PortableClassLibrary1" in the "FormsPortable1" portable library (that was created during step 1).

4. Add a "Visual C# -> Cross-Platform -> Forms Xaml Page" file named "Page1" to the "FormsPortable1" library.

5. Open `Page1.xaml.cs` and change the base class from `ContentPage` to `PortableClassLibrary1.PortableClassLibrary1`.

6. Wait for the IntelliSense to recognize `PortableClassLibrary1.PortableClassLibrary1` as a recognized type. This might take a few moments.

Now proceed with the original steps to replicate from Comment 0:

7. Make a modification to the `Page1.xaml` file and save it. It is sufficient just to overwrite the string "Page1" with "Page1" and save the file.

8. Navigate to the `Page1.xaml.cs` file to check the IntelliSense status of the "PortableClassLibrary1" namespace.

## Results

The "PortableClassLibrary1" namespace cannot be found.

### Error messages from "View -> Error List"

> Error	CS0246	The type or namespace name 'PortableClassLibrary1' could
> not be found (are you missing a using directive or an assembly
> reference?)
> FormsPortable1
> c:\source\FormsPortable1\FormsPortable1\FormsPortable1\Page1.xaml.cs

## Evaluation of possible workarounds

### Bug 33181, Comment 30: only helps temporarily

> The simple workaround is to remove and re-add the references from the
> App projects to the PCL.

Removing the reference that I added during step 3 and then repeating step 3 does _temporarily_ switch the error messages back to their original state from after step 6 [1]. But repeating step 7 causes the errors to switch right back. Unfortunately that means the workaround is not too helpful.

[1] The "namespace ... could not be found" error goes away, and the `InitializeComponent` error from Bug 33181 re-appears.

### Bug 33181, Comment 22: has no effect

The suggested `.targets` file helps with the `InitializeComponent` error (Bug 33181), but it has _no effect_ on the behavior of _this_ bug (Bug 32988) for types and namespaces in PCL references.
Comment 18 Brendan Zagaeski (Xamarin Team, assistant) 2016-03-23 02:45:48 UTC
The precise changes that introduced this bug are the modifications to `Xamarin.Forms.targets` from the following 2 commits:

0bb8c1e707273043ca522970bf206bb12a1c10d3 (Bug 29501)
7bf0bbead90c0383abdeefe376952357a9e04303 (Bug 32341)

## Workaround to revert those 2 commits by hand and apply an alternate fix for Bug 29501 and Bug 32341

1. Open `packages\Xamarin.Forms.*\build\portable-win+net45+wp80+win81+wpa81+MonoAndroid10+MonoTouch10+Xamarin.iOS10\Xamarin.Forms.targets` in the Visual Studio text editor.

(Replace `*` with the Xamarin.Forms version you're using. If you're using VS 2015 Update 1, you can instead make the changes in "%USERPROFILE%\.nuget\packages\Xamarin.Forms\*\build\portable-win+net45+wp80+win81+wpa81+MonoAndroid10+MonoTouch10+Xamarin.iOS10\Xamarin.Forms.targets". Then the changes will propagate any time you install that cached version of the package.)

2. Replace `PrepareResources` with `Compile` in the following lines:


... to change it back to:


3. Remove `PrepareResources;` from the following line:

<Target Name="UpdateDesignTimeXaml" Condition="'$(UseHostCompilerIfAvailable)' == 'true'" DependsOnTargets="PrepareResources; Compile"/>

... to change it back to:

<Target Name="UpdateDesignTimeXaml" Condition="'$(UseHostCompilerIfAvailable)' == 'true'" DependsOnTargets="Compile"/>

4. Add `BeforeTargets="XamlPreCompile"` to the following line:

<Target Name="XamlG" DependsOnTargets="$(XamlGDependsOn)"/>

... to change it to:

<Target Name="XamlG" BeforeTargets="XamlPreCompile" DependsOnTargets="$(XamlGDependsOn)"/>

(See Bug 39827, Comment 3 for additional information about this last change.)

## Results after making these changes

(Tested with Xamarin.Forms, except where otherwise noted.)

Bug 29501 - GOOD (Tested with Xamarin.Forms
Bug 32341 - GOOD
Bug 32988 - GOOD
Bug 33181 - GOOD
Bug 39827 - GOOD

## Remaining Questions

Of course, this workaround does not directly address the question of why running `PrepareResources` causes the Xamarin.Forms PCL project to temporarily "forget" the references to the secondary PCL project. So if the `PrepareResources` approach still has some important advantages over this alternate `XamlPreCompile` approach, then further investigation will be needed.
Comment 20 Jason Michas 2016-03-23 14:53:07 UTC
I am unable to get this workaround to work. I am using I made the changes to the targets file as described in comment #18. 

I did a clean and rebuild so all references were displayed as working and known to VS.

I opened a Xaml page and added a space and removed it to force a change. I saved the page and all the external PCL references in the Xaml file lit up red and were then unknown to VS. All intellisense for the external PCLs stopped working.
Comment 21 Victor Arce 2016-03-23 15:38:17 UTC
Jason Michas, replace Xamarin.Forms.targets with this: https://gist.github.com/victorarce/8f42ae855457275d1924 and restart Visual Studio.
Comment 22 Jason Smith [MSFT] 2016-03-23 17:03:21 UTC
@Brendan did you test in Xamarin Studio with that fix?
Comment 23 Brendan Zagaeski (Xamarin Team, assistant) 2016-03-23 19:23:38 UTC
@Jason, excellent point. Testing the `BeforeTargets="XamlPreCompile"` approach in Xamarin Studio on Mac does indeed reveal some problematic warnings because there is no `XamlPreCompile` target in that environment.

One possible alternative might be to discard `BeforeTargets="XamlPreCompile"` (step 4), and then use `CoreCompileDependsOn` rather than `CompileDependsOn` at step 2:


Step 3 stays the same:

<Target Name="UpdateDesignTimeXaml" Condition="'$(UseHostCompilerIfAvailable)' == 'true'" DependsOnTargets="Compile"/>

This seems to preserve all of the desired "good" behaviors in Xamarin Studio and Visual Studio that I have tested so far. Note to users watching this bug: A strong caveat is that at the moment the only evidence I am providing to support either this approach or the approach from Comment 18 is direct experimentation. To put it another way, I am not certain of the complete flow of execution through the targets when performing a "full" build or when updating the `.g.cs` files. So this approach might break some other scenarios that I haven't tried.

## Results with this slightly different approach

Bug 29501 - GOOD
Bug 32341 - GOOD
Bug 32988 - GOOD
Bug 33181 - GOOD
Bug 39827 - GOOD

Xamarin Customer Support
Comment 24 Jason Michas 2016-04-07 21:37:47 UTC
Sorry, its been a while since Ive been able to tinker with a Xamarin project. It seems that using the gist in comment #21 by victor does indeed fix the problem for me. Doing exactly the same steps as I described before (comment #20) no longer breaks all the references to external PCLs. This is awesome.
Comment 25 Brendan Zagaeski (Xamarin Team, assistant) 2016-04-09 02:59:59 UTC
## Verification status: verified fixed on Xamarin.Forms

GOOD: Xamarin.Forms
BAD:  Xamarin.Forms
Comment 27 Daniel Mercer 2016-04-15 08:57:25 UTC
@Brendan, is there a possible ETA for when Xamarin.Forms will be availible on a nu-get package?
Comment 28 Victor Arce 2016-04-15 14:31:33 UTC
@Daniel Mercer, its already on NuGet. Just be sure you checked "Include Pre-Releases" option in package manager to get pre-2. btw, I'm using VS2015.
Thanks @Brendan
Comment 29 Daniel Mercer 2016-04-15 15:27:09 UTC
Hi @Victor & @Brendan,

Thanks, After installing this I now end up with the following errors 

2>------ Build started: Project: ProjMobile.Droid, Configuration: Release Any CPU ------
2>C:\Program Files (x86)\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(348,2): error XA5207: Please install package: 'GPS AppIndexing' available in SDK installer. Java library file C:\Users\Daniel\AppData\Local\Xamarin\GooglePlayServices.AppIndexing\8.4.0\embedded\classes.jar doesn't exist.
2>C:\Program Files (x86)\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(348,2): error XA5206: Please install package: 'GPS AppIndexing' available in SDK installer. Android resource directory C:\Users\Daniel\AppData\Local\Xamarin\GooglePlayServices.AppIndexing\8.4.0\embedded\./ doesn't exist.
2>C:\Program Files (x86)\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(348,2): error XA5207: Please install package: 'GPS Base' available in SDK installer. Java library file C:\Users\Daniel\AppData\Local\Xamarin\GooglePlayServices.Base\8.4.0\embedded\classes.jar doesn't exist.
2>C:\Program Files (x86)\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets(348,2): error XA5206: Please install package: 'GPS Base' available in SDK installer. Android resource directory C:\Users\Daniel\AppData\Local\Xamarin\GooglePlayServices.Base\8.4.0\embedded\./ doesn't exist.
========== Build: 1 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
========== Deploy: 0 succeeded, 0 failed, 0 skipped ==========

cant seem to get past this now.. checked with the SDK manager, I have the latest SDK's installed for 6.0 android and all the additional google play services installed. I've also tried installed them via the NuGet packages but again that doesn't seem to fix it either. any suggestions?
Comment 30 Victor Arce 2016-04-15 15:47:46 UTC
@Daniel Mercer, sorry to hear that. I had only tested on iOS, but I just did Droid and even tough it updated a lot of android dependencies, it compiled OK. It looks like you have a problem only with "GPS AppIndexing"... try the usual: clean, reinstall, etc. Try removing it to see if thats the only problem.