The world is changing so fast I updated ReactiveUI version on my project and my code does not compile anymore. In this particular case I cannot see .Subscribe() on ReactiveCommand anymore. The closest I found was .SubscribeToExpressionChain() which I have no idea what it is. The documentation or even the code sample on their main Repo's Readme.MD continues to say and/or assume ReactiveCommand is an IObservable. Where do I access latest documentation? Am I missing any obvious clue here?
Reactive commands are themselves observable. Whenever any execution of the command completes, the result will tick through the command itself.
So it turns out the basic ReactiveCommand type is just an abstract type and does not support IObservable. My member types were ReactiveCommand instead of ReactiveCommand<TParam, TResult> which they should have been.
Related
I'm trying to port my console app over to a Blazor app. Everything worked fine inside the console type project, but it's not inside the Blazor project so I'm trying to troubleshoot. The app calls some things from a separate "class library" type project within the same solution.
The troubleshooting process itself is having issues of its own though. After a little bit of confusion I realized that the breakpoints set inside the referenced class library type project's code are not being hit.
Checking to console, I see it gives the error:
L: Unable to insert breakpoint at FtxApi.FtxWebSocketApi/<Test>d__5:MoveNext ():15
Is there anything I need to do (project settings or something) for the debugger to hit these? Or is it not supported at the moment?
Right now I'm just using a lot of Console.Writeline sort of as a workaround/replacement. And I noticed that the Console.Writelines inside the referenced class library type project are being called.. but only up to a certain method call that comes from a third party package. Execution seems to return from that point (nothing is called after it). Not sure what's going wrong there - more troubleshooting is needed, which brings us back to the breakpoints not firing (ideally I'd be able to make use of them).
I understand Blazor is new (and I'm an absolute beginner at using it), so not everything needs or is going to be perfect. I'm asking about the breakpoints kind of out of curiosity (I'd like to get them working but no big deal otherwise).
What I'd really like some insight into is: What might be going on with the code seemingly stopping execution / returning at that one particular method call? The method I'm calling is WebSocket.Open(), from the package WebSocket4Net. As mentioned above, I've tested this before (in a Console app) and it worked fine, so I'm guessing it's somehow related to Blazor which I'm unfamiliar with. I'm unsure how to get any more info to help debug this problem. Any help appreciated.
Edit:
I managed to find a solution to my problem without the use of debugging tools like breakpoints and such (I just used Console.Writeline a lot). I guess Blazor does not support some websocket implementations or something, because I found this error: System.PlatformNotSupportedException: Operation is not supported on this platform. blazor.webassembly.js:1 at System.Net.Sockets.Socket coming from websocket.Open(). I managed to get it working by implementing System.Net.Websockets instead, similar to this. Though my troubleshooting is over (for now), I'm still wondering if it's somehow possible to use breakpoints inside other referenced projects.
There are 2 solutions:
Solution 1: Right-click at Solution, choose Properties, choose Common Properties, Choose Multiple startup project, choose Action Start for Foo.Client, Foo.Server, Foo.Shared . Something like this
See https://blog.magnetismsolutions.com/blog/paulnieuwelaar/2015/04/07/debug-multiple-projects-at-the-same-time-in-visual-studio
Solution 2: Compile SharedProject, attacht PDB for debugging.
https://learn.microsoft.com/en-us/visualstudio/debugger/how-to-debug-an-executable-not-part-of-a-visual-studio-solution?view=vs-2019
Take the hello-world as an example.
I have couple of questions:
What does v8::Isolate do? Does it create an new thread
What does v8::Isolate::Scope do?
What does v8::HandleScope do?
What does v8::Local<v8::Context> do?
What does v8::Script::Compile do? Does it compile the js code directly to machine code?
Thanks your for your help!
See the official wiki:
An isolate is a VM instance with its own heap.
A local handle is a pointer to an object. All V8 objects are accessed using handles, they are necessary because of the way the V8 garbage collector works.
A handle scope can be thought of as a container for any number of handles. When you've finished with your handles, instead of deleting each one individually you can simply delete their scope.
A context is an execution environment that allows separate, unrelated, JavaScript code to run in a single instance of V8. You must explicitly specify the context in which you want any JavaScript code to be run.
These concepts are discussed in greater detail in the Embedder's Guide.
Once you've read the existing documentation, if anything is still unclear, please ask more specific questions.
Regarding (5): In current versions of V8, v8::Script::Compile compiles bytecode for V8's interpreter. In earlier versions, it compiled unoptimized machine code. The difference is an internal implementation detail that you don't need to worry about :-)
The following query works in Debug mode only:
private IQueryable<UserState> UsersOfEmail(string email)
{
return this.realm.All<UserState>()
.Where(u => u.EmailAddress == email);
}
When in Release mode, I get the error:
The rhs of the binary operator 'Equal' should be a constant or closure variable expression
I found a workaround for the error, but it doesn't seem to apply here.
When I check the Enable debugging option for the project (iOS, in this case), it works fine, which is why it was working in Debug mode only in the first place.
Any clue on the relationship between the error and the debugging option?
UPDATE
After further investigation, I found out that this issue has no relation to Realm.
I was misusing the event pub-sub feature of Prism (MVVM framework, among other things), and subscribing multiple times to an event in a view model of a page that would be navigated to and from, without unsubscribing in each interaction.
I thought this was a Realm issue because I didn't realize at first that the email parameter was null when in Release mode.
By using the pub-sub correctly, I was able to mitigate the problem. I still don't have an answer as to why it was only happening in Release mode, even though the Linking option was disabled in both build modes.
We have a new release coming out soon which uses relinq to handle expression parsing and should dramatically improve how we handle linq, especially for this kind of expression.
It will be the next release after 0.77.2.
However, you are the first to identify something failing only in a Release mode so there may be something more complex going on.
Is there any difference in the Linking settings between your simple and complex apps? Maybe linker stripping is causing some problems.
I'm currently dealing with a part-time (and annoying) bug with some extension methods in VB .NET (VS 2010 and VS 2008).
I have some client projects that use some extension methods from a "Framework" Project I created for general purpose.
However, sometime, when a try to start the solution, I get a long list of error saying the extension method "is not a member of" target object.
When this happen, I can rebuild the solution without getting any error but if I start the project again, the same error will be raised again.
So far I have 2 workaround
A) Go on the extension method definition, delete the tag, compile (with error), put the tag back.
B) Close Visual Studio et re-open it.
Is there any betterway to handle this problem?
There is an active bug report for this problem at Connect. There's a dire need for a repro, a project with specific steps to let them reproduce the issue in-house. Perhaps you can help, it's what it will take to solve it or recommend a workaround.
EDIT: one late addition to this answer, since I've posted this there have been additional questions that note a problem with the IntelliSense parser behaving different from the compiler. There's an issue with the multi-targeting feature, particularly in VS2010, triggered by the Client Profile option for .NET 4. It is the default for a new project. What goes wrong is adding an assembly reference that requires the full profile, commonly because of a dependency on System.Web. You'll get a warning for that, but that's quickly blown away with a large number of errors. The fix is to change the project's Framework Target from client to full.
I've recently encountered this same issue. My project would Build just fine but if I tried to use the Rebuilt option I would get the error about my extension methods not being found on the objects they were extending.
I have managed to fix this today by including an Import at the top of the classes using the Extension method.
So at the top of the file I actually have
Imports project_name.extension_module
I have no idea why this is required but it fixes the problem in my case. I hope this helps somebody else that has wasted as much time with this as I have!
Liam
A less time consuming work around than the two you listed is to "Rebuild Solution" instead of the normal Build Solution. This has always worked for me whenever I run into this problem.
We have something very similar. Call extensions merhod that extends type A. type is actually an instance of type B that implements interface C. interface C has a method with the same name as extension method.
Interface C declares method Foo
Class B inherits from A implements C
Static Class
Static method Foo (this A)
If A is C
(A as C).Foo
When debugging on the line if A is C it actually calls Foo multiple times and you can step at assembly level and see it indicates it is doing the comparison. The way we demonstrate that the call is happen Foo executes a sql statement and we can see sql profiler executing the code in Foo.
Change A as C to reflection and bug goes away. Or use debugger hidden/step through and bug is masked. Also if you micro-step the sql profiler shows the query is getting called multiple times (before Foo is actually called) for each assembly statement.
I have been tracing a BAD_ACCESS error using NSZombieEnabled. As error I get returned:
*** -[MyDocument respondsToSelector:]: message sent to deallocated instance 0x2671b0
I do know what this means,however what surprises me is that I don't call this function anywhere, not in MyDocument.m nor in any imported files.To be exact, I don't call this at all in my whole project. The debugger will not go to the actual code that causes the error, but only shows the assembly code, which, when I click on it, gives me and even bigger list of not understandable numbers.
Does anyone have an idea where this weird "respondsToSelector" could come from? Maybe from frameworks I am using? I am really confused.
Thanks for any help!
respondsToSelector: is widely used in frameworks. For instance, if your class is a delegate or data source (highly likely for MyDocument) the delegating object will use it to determine which delegate methods you support.
In general, the way to find out where a problem like this is happening is to set a breakpoint on objc_exception_throw() (Run->Show->Breakpoints, double-click where it says “Double-Click for Symbol”, type objc_exception_throw) and run under the debugger (Build->Build and Debug - Breakpoints On).