Develop Reference

How do I prevent Xamarin Forms apps from breaking, when I switch between different projects/apps?

I have multiple Xamarin Forms projects for different apps.
Sometimes when I switch between the projects or create a new one, every single app shows one of various error messages, preventing it from starting.
Usually I "fix" this, by deleting the broken project and restarting my computer, however this time it still doesn´t work. The error messages keep showing up, even my main project (which usually works fine) is bugged now.
Is there some sort of cache or some process that I can delete? Does someone know any other way of fixing this without deleting projects?
Each project seems to have different issues, here are 3 of the error messages that appear. I didn´t copy the other ones when I had the chance.
First:
Fehler Fehler beim Generieren des Java-Typs für die Klasse "AndroidX.Core.View.Accessibiity.AccessibilityManagerCompat/IAccessibilityStateChangeListenerImplementor" aufgrund von MAX_PATH: System.IO.DirectoryNotFoundException: Ein Teil des Pfades "C:\Users\trygve.defreese\source\repos\Eigen\Vorlagen\Mehrsprachigkeit mit I18n\LanguageSupportI18n\LanguageSupportI18n.Android\obj\Debug\110\android\src\mono\androidx\core\view\accessibility\AccessibilityManagerCompat_AccessibilityStateChangeListenerImplementor.java" konnte nicht gefunden werden.
bei System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
bei System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy, Boolean useLongPath, Boolean checkHost)
bei System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize)
bei Microsoft.Android.Build.Tasks.Files.CopyIfStreamChanged(Stream stream, String destination) in /Users/builder/azdo/_work/2/s/xamarin-android/external/xamarin-android-tools/src/Microsoft.Android.Build.BaseTasks/Files.cs:Zeile 170.
bei Xamarin.Android.Tasks.GenerateJavaStubs.CreateJavaSources(IEnumerable`1 javaTypes, TypeDefinitionCache cache). LanguageSupportI18n.Android
Second:
Fehler MSB4018 Unerwarteter Fehler bei der XamlCTask-Aufgabe.
System.Runtime.Serialization.SerializationException: Die Assembly "Mono.Cecil, Version=0.10.3.0, Culture=neutral, PublicKeyToken=50cebf1cceb9d05e" kann nicht gefunden werden.
Server stack trace:
bei System.Runtime.Serialization.Formatters.Binary.BinaryAssemblyInfo.GetAssembly()
bei System.Runtime.Serialization.Formatters.Binary.ObjectReader.GetType(BinaryAssemblyInfo assemblyInfo, String name)
bei System.Runtime.Serialization.Formatters.Binary.ObjectMap..ctor(String objectName, String[] memberNames, BinaryTypeEnum[] binaryTypeEnumA, Object[] typeInformationA, Int32[] memberAssemIds, ObjectReader objectReader, Int32 objectId, BinaryAssemblyInfo assemblyInfo, SizedArray assemIdToAssemblyTable)
bei System.Runtime.Serialization.Formatters.Binary.__BinaryParser.ReadObjectWithMapTyped(BinaryObjectWithMapTyped record)
bei System.Runtime.Serialization.Formatters.Binary.__BinaryParser.ReadObjectWithMapTyped(BinaryHeaderEnum binaryHeaderEnum)
bei System.Runtime.Serialization.Formatters.Binary.__BinaryParser.Run()
bei System.Runtime.Serialization.Formatters.Binary.ObjectReader.Deserialize(HeaderHandler handler, __BinaryParser serParser, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage)
bei System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize(Stream serializationStream, HeaderHandler handler, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage)
bei System.Runtime.Remoting.Channels.CrossAppDomainSerializer.DeserializeObject(MemoryStream stm)
bei System.Runtime.Remoting.Messaging.SmuggledMethodReturnMessage.FixupForNewAppDomain()
bei System.Runtime.Remoting.Channels.CrossAppDomainSink.SyncProcessMessage(IMessage reqMsg)
Exception rethrown at [0]:
bei System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
bei System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
bei Microsoft.Build.Framework.ITask.Execute()
bei Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute()
bei Microsoft.Build.BackEnd.TaskBuilder.<ExecuteInstantiatedTask>d__26.MoveNext() BDE_App C:\Program Files (x86)\Microsoft\Xamarin\NuGet\xamarin.forms\5.0.0.2012\buildTransitive\Xamarin.Forms.targets 119
Third(this one appeared 15 times at once):
Schweregrad Code Beschreibung Projekt Datei Zeile Unterdrückungszustand
Fehler failed to open directory: Das System kann die angegebene Datei nicht finden. (2). Testprojekt5.Android C:\Users\trygve.defreese\source\repos\Eigen\Übungen\Testprojekt5\Testprojekt5.Android\obj\Debug\110\lp\51\jl\res
Edit:
Steps to reproduce the issue:
Open a Xamarin Forms project
Load project to mobile device
Open a second Xamarin Forms project, leaving the first one open
Load second project to mobile device
This usually provokes the issue, I cannot guarantee it though.

How to fix TFS build issue "ResolveComReference" task failed unexpectedly process can't access file System.Windows.Interactivity.resources.dll'

I have a WPF solution and I'm using Visual Studio Team Services with TFVC for source control. I've created an automated build, however, the build will fail (sporadically) with the following error:
C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Microsoft.Common.targets (2015, 0)
The "ResolveComReference" task failed unexpectedly.
System.IO.IOException: The process cannot access the file 'C:\a\bin\es\System.Windows.Interactivity.resources.dll' because it is being used by another process.
Server stack trace:
at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
at System.IO.File.InternalCopy(String sourceFileName, String destFileName, Boolean overwrite, Boolean checkHost)
at Microsoft.Build.Tasks.Copy.CopyFileWithLogging(FileState sourceFileState, FileState destinationFileState)
at Microsoft.Build.Tasks.Copy.DoCopyWithRetries(FileState sourceFileState, FileState destinationFileState, CopyFileWithState copyFile)
at Microsoft.Build.Tasks.NativeMethods.QueryPathOfRegTypeLib(Guid& clsid, Int16 majorVersion, Int16 minorVersion, Int32 lcid)
at Microsoft.Build.Tasks.ComReference.GetPathOfTypeLib(TaskLoggingHelper log, Boolean silent, TYPELIBATTR& typeLibAttr, String& typeLibPath)
at Microsoft.Build.Tasks.ResolveComReference.ConvertAttrReferencesToComReferenceInfo(List`1 projectRefs, ITaskItem[] typeLibAttrs)
at Microsoft.Build.Tasks.ResolveComReference.Execute()
at System.Runtime.Remoting.Messaging.StackBuilderSink._PrivateProcessMessage(IntPtr md, Object[] args, Object server, Object[]& outArgs)
at System.Runtime.Remoting.Messaging.StackBuilderSink.SyncProcessMessage(IMessage msg)
Exception rethrown at [0]:
at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
at Microsoft.Build.Framework.ITask.Execute()
at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute()
at Microsoft.Build.BackEnd.TaskBuilder.<ExecuteInstantiatedTask>d__1.MoveNext()
When this does occur.. I can queue another build and it will pass. Does anyone know why this may be happening and how it can be fixed?

AppDomainUnloadedException when TFS is cloning git repos for a build

Suddenly, when queuing builds in TFS based on a git team project, I get the following stack trace.
Exception Message: Attempted to access an unloaded AppDomain. (type
AppDomainUnloadedException) Exception Stack Trace: Server stack
trace: at
LibGit2Sharp.Core.NativeMethods.git_clone(RepositorySafeHandle& repo,
String origin_url, FilePath workdir_path, GitCloneOptions& opts) at
LibGit2Sharp.Core.Proxy.git_clone(String url, String workdir,
GitCloneOptions& opts) at LibGit2Sharp.Repository.Clone(String
sourceUrl, String workdirPath, CloneOptions options) at
Microsoft.TeamFoundation.Build.Activities.Git.GitPull.GitClone.GetRepository(String
repositoryUrl, String workingFolder, Boolean checkoutSubmodules) at
System.Runtime.Remoting.Messaging.StackBuilderSink._PrivateProcessMessage(IntPtr
md, Object[] args, Object server, Object[]& outArgs) at
System.Runtime.Remoting.Messaging.StackBuilderSink.AsyncProcessMessage(IMessage
msg, IMessageSink replySink)
Exception rethrown at [0]: at
System.Runtime.Remoting.Proxies.RealProxy.EndInvokeHelper(Message
reqMsg, Boolean bProxyCase) at System.Func4.EndInvoke(IAsyncResult
result) at
Microsoft.TeamFoundation.Build.Activities.Git.GitPull.GitRepositoryBase.EndExecute(AsyncCodeActivityContext
context, IAsyncResult result) at
System.Activities.AsyncCodeActivity1.System.Activities.IAsyncCodeActivity.FinishExecution(AsyncCodeActivityContext
context, IAsyncResult result) at
System.Activities.AsyncCodeActivity.CompleteAsyncCodeActivityData.CompleteAsyncCodeActivityWorkItem.Execute(ActivityExecutor
executor, BookmarkManager bookmarkManager)
I changed nothing for this to happend, googling so far I found info about it perhaps being macafee, but we dont use that on our build agent.
Using an on-premises build server
Normal TFS team projects build as expected

Resolved by restarting the server - not sure how I didn't think of that.

PermissionSet - Request Failed error

I have few projects communicating using ChannelSink, ServerSink and ClientSink.
I've upgraded the projects from .NET 2.0 to .NET 4.0. Before the upgrade everything worked fine.
Now, when I try to communicate , - for a specific message - my OnReceiveMessage isn't called and throwing the following exception:
System.Security.SecurityException: Request failed
Server stack trace:
at System.Array.InternalCreate(Void* elementType, Int32 rank, Int32* pLengths, Int32*
pLowerBounds)
at System.Array.CreateInstance(Type elementType, Int32 Length)
at System.Runtime.Serialization.Formatters.Soap.ObjectReader.ParseArray(ParseRecord
pr)
at System.Runtime.Serialization.Formatters.Soap.ObjectReader.ParseObject(ParseRecord
pr)
at System.Runtime.Serialization.Formatters.Soap.ObjectReader.Parse(ParseRecord
pr)
System.Runtime.Serialization.Formatters.Soap.SoapHandler.StartChildren()
at System.Runtime.Serialization.Formatters.Soap.SoapParser.ParseXML()
System.Runtime.Serialization.Formatters.Soap.ObjectReader.Run()
System.Runtime.Serialization.Formatters.Soap.ObjectReader.Deserialize(HeaderHandler,
ISerParser
serParser)
System.Runtime.Serialization.Formatters.Soap.SoapFormatter.Deserialize(Stream
serializationStream,
HeaderHandler handler)
at System.Runtime.Remoting.Channels.CoreChannel.DeserializeSoapRequestMessage(Stream
inputStream, Header[] h, Boolean bStrictBinding)
at System.Runtime.Remoting.Chanels.SoapServerFormatterSink.ProcessMessage
(IServerChannelSinkStack sinkStack, IMessage requestMsg,
ITransportHeaders requestHeaders, Stream
requestStream, IMessage& responseMsg, ITransportHeaders&
responseHeaders, Stream& responseStream)
Exception rethrown at [0]:
at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage (IMessage reqMsg, IMessage
retMSg)
at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData&
msgData, Int32 type)
.
. (some of my files)
. The action that failed was: Demand The type of the first permission that failed was: System.Security.PermissionSet The demand
was for:
The only permitted permissions were:
The method that caused that failure was:
System.Runtime.Remoting.Channels.ServerProcessing
ProcessMessage(System.Runtime.Remoting.Channels.IServerChannelSinkStack,
System.Runtime.Remoting.Messaging.IMessage,
System.Runtime.Remoting.Channels.ITransportHeaders, System.IO.Stream,
System.Runtime.Remoting.Messaging.IMessage ByRef,
System.Runtime.Remoting.Channels.ITransportHeaders ByRef,
System.IO.Stream ByRef)
The thing is, if I create a dummy method and add it to the sinkstack - it calls it. even if I use the same proxy which denies the message.
Other thing is, The other messages are working just fine. only one type of messages isnt working from all the types iv'e created.
I haven't requested PermissionSet at my app at all, Any help?

Pah - should have guess that 5 minutes after posting on stack exchange I would find it. I simply had to replace:
<formatter ref="soap" />
by
<formatter ref="soap" typeFilterLevel="Full" />
The MSDN documentation for typeFilterLevel explains what's happening, although I'm not entirely sure why an array isn't considered a "basic" type

"Value cannot be null" when invoking method decorated with [Autocomplete]

I have a Windows Forms application (.NET 3.5) which is deployed with the ClickOnce-technology and is used by approximately 50-100 concurrent users. They all target the same MS SQL database (SQL SERVER 2008 R2) which is hosted externally.
The application itself uses a "wrapper"-class to perform database queries. This class derives from ServicedComponent and decorates its methods with the [AutoComplete] attribute. Below is an example:
[Serializable]
[Transaction(TransactionOption.Required, Isolation=TransactionIsolationLevel.ReadCommitted)]
public class CTxGreenfee374Processor: ServicedComponent
{
public CTxGreenfee374Processor() { }
[AutoComplete]
internal Season SaveSeason(CallContext callContext, Season season)
{
return new PGreenfee374Processor().SaveSeason(callContext, season);
}
}
Most of the time this approach works like a charm. But numerous times a day following exception occur when this method gets invoked (of course there are similar methods with this exact problem):
System.ArgumentNullException
Value cannot be null.
Server stack trace:
at System.Threading.Monitor.Enter(Object obj)
at System.Data.ProviderBase.DbConnectionPool.TransactedConnectionPool.TransactionEnded(Transaction transaction, DbConnectionInternal transactedObject)
at System.Data.ProviderBase.DbConnectionPool.TransactionEnded(Transaction transaction, DbConnectionInternal transactedObject)
at System.Data.ProviderBase.DbConnectionInternal.CleanupConnectionOnTransactionCompletion(Transaction transaction)
at System.Data.SqlClient.SqlDelegatedTransaction.SinglePhaseCommit(SinglePhaseEnlistment enlistment)
at System.Transactions.TransactionStateDelegatedCommitting.EnterState(InternalTransaction tx)
at System.Transactions.TransactionStateDelegated.BeginCommit(InternalTransaction tx, Boolean asyncCommit, AsyncCallback asyncCallback, Object asyncState)
at System.Transactions.CommittableTransaction.Commit()
at System.EnterpriseServices.TransactionProxy.Commit(Guid guid)
at System.Runtime.InteropServices.Marshal.ThrowExceptionForHRInternal(Int32 errorCode, IntPtr errorInfo)
at System.EnterpriseServices.Thunk.Callback.DoCallback(Object otp, IMessage msg, IntPtr ctx, Boolean fIsAutoDone, MemberInfo mb, Boolean bHasGit)
at System.EnterpriseServices.ServicedComponentProxy.CrossCtxInvoke(IMessage reqMsg)
at System.EnterpriseServices.ServicedComponentProxy.Invoke(IMessage request)
at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
at GOLFIT.BusinessProcess.Economics.CTxGreenfee374Processor.SaveSeason(CallContext callContext, Season season)
at GOLFIT.BusinessProcess.Economics.Greenfee374Processor.SaveSeason(CallContext callContext, Season season) in C:\Projekt\GOLFIT\DEVELOPMENTPROD374\BusinessProcess\GOLFIT.BusinessProcess.Economics\Greenfee374\Greenfee374Processor.cs:line 104
at System.Runtime.Remoting.Messaging.StackBuilderSink._PrivateProcessMessage(IntPtr md, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext, Object[]& outArgs)
at System.Runtime.Remoting.Messaging.StackBuilderSink.PrivateProcessMessage(RuntimeMethodHandle md, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext, Object[]& outArgs)
at System.Runtime.Remoting.Messaging.StackBuilderSink.SyncProcessMessage(IMessage msg, Int32 methodPtr, Boolean fExecuteInContext)
Exception rethrown at [0]:
at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
at GOLFIT.BusinessProcess.Economics.Greenfee374Processor.SaveSeason(CallContext callContext, Season season)
at GOLFIT.WinGUI.Economics.FrmPrice374.Save(Boolean refresh).
As you can see the method SaveSeason in the CTxGreenfee374Processor class is mentioned in the exception. As far as I can see this is the last trace of code that I've written.
My only clue is that the exception has something to do with the [AutoComplete] attribute and/or the derived ServicedComponent class. This conclusion is based on that I've checked for invalid input parameters and that no code inside the method gets executed before the exception. And I assume that both ServicedComponent class and [AutoComplete] attribute performs som kind of logic before the method block executes.
I haven't been successful in recreating this exception when debugging, due to inconsequent occurrences of this exeption. So I've had to depend on logs from the production application.
If anyone got an idea regarding this problem it would be extremely appreciated!