Xamarin Studio community treats handled exception as unhandled exception - xamarin

Question

I have this problem where I get unhandled exception crash on my Xamarin Android app. I'm trying to login user into parse.com using user session token. The statements are put inside try-catch block to catch exceptions. But catch block fails to catch "Invalid session token" error from parse.com and app crashes. Catch block works fine if I manually tamper sessionToken.
Here's what I am doing
try {
await ParseUser.BecomeAsync(sessionToken);
...
} catch (Exception e){
//log exception
}
when there is invalid session token error, above code crashes saying "unhandled exception...." even though it was put inside try block.
following code works. (manually tampering token)
try {
await ParseUser.BecomeAsync(sessionToken + "test");
...
} catch (Exception e){
//log exception
}
Parse component from Xamarin Component store
What am I missing?
Also, same code works just fine with Xamarin.iOS.
EDIT Adding StackTrace
at Parse.Internal.ParseCommandRunner+<>c__DisplayClass2.<RunCommandAsync>b__1 (System.Threading.Tasks.Task`1[TResult] t) [0x000eb] in <5d1c0c2b96a7483d85e5c63b3e156125>:0
at Parse.Internal.InternalExtensions+<>c__DisplayClass1`2[TIn,TResult].<OnSuccess>b__0 (System.Threading.Tasks.Task t) [0x00000] in <5d1c0c2b96a7483d85e5c63b3e156125>:0
at Parse.Internal.InternalExtensions+<>c__DisplayClass7`1[TResult].<OnSuccess>b__6 (System.Threading.Tasks.Task t) [0x0006f] in <5d1c0c2b96a7483d85e5c63b3e156125>:0
at System.Threading.Tasks.ContinuationResultTaskFromTask`1[TResult].InnerInvoke () [0x00024] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Threading.Tasks.Task.Execute () [0x00010] in <3fd174ff54b146228c505f23cf75ce71>:0
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in <3fd174ff54b146228c505f23cf75ce71>:0
at Parse.Internal.InternalExtensions+<>c__DisplayClass7`1[TResult].<OnSuccess>b__6 (System.Threading.Tasks.Task t) [0x00033] in <5d1c0c2b96a7483d85e5c63b3e156125>:0
at System.Threading.Tasks.ContinuationResultTaskFromTask`1[TResult].InnerInvoke () [0x00024] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Threading.Tasks.Task.Execute () [0x00010] in <3fd174ff54b146228c505f23cf75ce71>:0
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in <3fd174ff54b146228c505f23cf75ce71>:0
at Parse.Internal.InternalExtensions+<>c__DisplayClass7`1[TResult].<OnSuccess>b__6 (System.Threading.Tasks.Task t) [0x00033] in <5d1c0c2b96a7483d85e5c63b3e156125>:0
at System.Threading.Tasks.ContinuationResultTaskFromTask`1[TResult].InnerInvoke () [0x00024] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Threading.Tasks.Task.Execute () [0x00010] in <3fd174ff54b146228c505f23cf75ce71>:0
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x0003e] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x00028] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x00008] in <3fd174ff54b146228c505f23cf75ce71>:0
at System.Runtime.CompilerServices.TaskAwaiter`1[TResult].GetResult () [0x00000] in <3fd174ff54b146228c505f23cf75ce71>:0
at Hyphen_App.Droid.SplashActivity+<setCurrentUser>d__4.MoveNext () [0x00035] in /Chethan Shetty/GIT/android-parent/Hyphen_App.Droid/Splash/SplashActivity.cs:112
EDIT 1 After changing setCurrentUser to following, I am able to catch the exception but after 3-4 seconds app crashes by itself giving " System.AggregateException"
void setCurrentUser(string sessionToken,Action<bool> callback){
try {
ParseUser.BecomeAsync(sessionToken).Wait();
callback(true);
}catch(AggregateException e){
e.Handle( x => { return true; });
callback(false);
}

Answer 1

Like you said in the comments you were calling the async method in your OnCreate without awaiting it.
It can cause the Exception not to be caught, if the somewhere in the async stack a task is not awaited.
I hope it helped you resolve the issue.
Update
Sorry for not expressing me clearly. Your code must look something like that:
protected override async void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
await this.SetCurrentUser();
}
private async Task<bool> SetCurrentUser(string sessionToken)
{
try {
await ParseUser.BecomeAsync(sessionToken);
} catch (Exception e) {
return false;
}
}
to use the await keyword was what i was referring to when saying 'awaiting'.
With the async / await keywords in C#, callbacks are rarely used in asynchronous scenarios anymore. There is a short introduction over at microsoft docs