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We are in the process of Architecting a mobile app to be developed using Qt and Azure Mobile Services. Coming from C#.Net background and worked on WPF applications, it's something new for us. We have used MVVM, MVP in past along with Layered architecture.
Which architecture pattern will be the best fit for this kind of application?
Read about Layered and Onion architectures. Onion architecture provides loose coupling in a better way and adhere to DDD somewhat.
Please suggest if something else will be a good fit.
Also, like to know which development methodology(DDD/BDD/TDD) shall be used considering the duration to be 4 months.
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Why are you looking at it from the wrong end? The first thing you need to do is to get the overall design of the application worked out. Only then can you really see which patterns, methodologies etc will fit with what you are trying to create.
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Thanks Richard. Can you suggest what should be covered in overall design? Is it going to UML diagrams(Component, Class, Use case). In Agile world, how much design would be enough for such an application.
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Well you know what you want this application to do, so you should be able to identify all its requirements and get them documented. Like I said above, you need to get your design complete first, then you can start looking at what processes and patterns would be most useful to turn that design into a working product.
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The question looks quite blunt.
MVVM, AFAIK it's like a MS trademarked one. (Though there are a pile of frameworks for Web-client). It's tightly bound with WPF/SL & similar MS frameworks.
MVP/ MVC, unless it's with frameworks like Cocoa (mac) & Asp.net MVC, which gives you some guidelines with implementations, it's just a pattern you can implement anywhere by yourself.
All these what we are talking about is UI design patterns.
And the link you've shared talks about Software Architecture in general.
First decide what UI pattern framework is available right out of the box in Qt. This is just for the UI to Data binding design.
The rest is the whole story. It all depends on what you need in your App. You can create you own "patterns" as per your need!
Starting to think people post kid pics in their profiles because that was the last time they were cute - Jeremy.
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Hi all,
I'm contemplating what would be a good approach to find all the files of a certain filetype (*.bgl) that a third-party (unmanaged) application loads into memory - basically to get an overview of names and paths of them.
Could someone of you please give me a hint or reading sources? I found the article "C# How to Scan a Process' Memory" but I'm too unexperienced to tell if that approach makes sense for retrieving a filelist only.
Thank you very much in advance,
Mick
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The only way to do that would be by what is known as "hooking", whereby you intercept API requests and examine the content of the parameters before passing the request on to the operating system for processing. Once an application has loaded all or part of a file into memory then there is no way to find its name.
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Thank you for the first clue, Richard!
After reading a little bit about hooking, I'm not quite sure if it would become a challenge or a torture, given my programming experience. But I want to give it a try. I also stumbled upon the "EasyHook" project, which seems to make things much easier in .NET, and will start reading the documentation later... maybe there are more hints or examples.
I guess it would help me if you had an idea which of the different Windows API hooks to use in order to find which files the exe loads?
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You probably need to check all API calls connected with file I/O; search in MSDN for the documentation.
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Sorry, Eddy - I guess I don't get it right. Followed the link, but neither the thread nor the links in it lead me to anything I could even dream about understanding  But you're right about the game thing  FSX
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That's why there's a warning in the stackoverflow thread; it is not an easy task - hooking isn't, and writing a filter isn't either.
Look at it this way; there'll be few developers who can say they tried something similar. There'd be quite some people waiting for an article on "how" you did so 
Bastard Programmer from Hell 
If you can't read my code, try converting it here[^]
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I look at it the way you suggest and drop that idea. Thank you though, saved me a lot of time and coffee. 
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I have developed some code in C++ which creates a bitmap, manipulates the bitmap with Direct2D, encodes the bitmap as a jpeg and returns the image as a stream. In a .net MVC project I am importing the C++ function using Platform Invoke.
Calling the C++ function from within the C# .net MVC app works fine and an image is received as a stream. However currently when the C++ code is called it starts up and then when it returns it shuts down. I would like the C++ code to maintain a state which persists from one time it is called to the next and the next after that etc.
How can I achieve this on Windows? I have been investigating Windows Services, however I have not seen any examples of returning data to the calling code (Service control program). Is this possible with a Windows Service? Could an image be returned from a call to a Windows Service as a stream?
Or am I looking in the wrong direction? Is there a more natural way to develop a C++ program which can be called from C#, returns a Stream and maintains a state? Could this even be achieved with Platform Invoke?
Kind Regards,
Duncan.
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If you want to maintain state you can do it in one of 2 ways.
If your application needs to regularly perform tasks whether a method is called or not, a Windows Service is the correct approach and you can communicate with it using some form of IPC. Microsoft gives an overview of various .NET IPC techniques at:
Interprocess Communications (Windows)[^]
The other mechanism that you can use is a persistence framework of some sort; i.e a database connection or a file. The easiest route would be to create a StateTracker object that serializes to a specific file. Load that file when your application is called and modify it as appropriate.
Actually, there's another pattern that you could follow, and that would be for your MVC application to track state and pass it to the class library when it calls methods. Bear in mind that IIS will manage memory for you, so may clear out any cache that you define, but this way you can leverage the same database used by your MVC app to store a StateTracker.
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Member 12424215 wrote: returns the image as a stream...which persists from one time it is called to the next and the next after that
Why. If it hands you a stream what do you think it is going to do in the future? Not like it can take the stream back.
Perhaps you want it to cache the stream and then update if there are changes? Thus if the next time it is invoked the changed or not changed stream is returned?
But is so how often is this called and how often is it changed. And how big is it in the first place?
Those are relevant because caching is done for performance reasons. Which you should only do if you have identified an actual performance problem. And the answer to the above would be relevant to that.
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Hello Folks,
Recently I came across a situation where an application is doing so much processing/storing data inside application domain itself without using cache or database for it. obviously in the end everything goes in to db, but say for some time it stays in application domain, and all the objects, list of objects created reside in application memory. and these objects and lists are being updated frequently as well.
Although it is not creating problem till now but it is general thinking that we should be able to drive this application from multiple application servers, thus dividing application load to multiple servers or processes.
What can be the possible solution one can suggest for this situation. any help will be appreciated.
Thanks
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I think you need to look closely at the application's design.
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girishmeena wrote: Although it is not creating problem till now but it is general thinking that we should be able to drive this application from multiple application servers,
Sounds potentially like over-engineering.
Does the company have sales/growth goals or estimates which will directly impact the size of the data set. Do you have performance measurements that track the time and size of this processing by which you can correlate to those business numbers?
If you have neither then perhaps it is time for the developers to ask sales/business for the first set. And if there are none perhaps time for development to ask sales/business what they actually need to help them create more profit and/or reduce costs.
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In most object-oriented programming languages (such as C#, Java and Visual Basic .NET), static signifies that the method or field does not exist on a particular instance in the application. Static methods/fields must only depend on their parameters and/or other static contexts, a single instance of whom will exist throughout the application lifetime.
The following only for programming languages that compile libraries to object code and not native assembly code:
In executable assemblies, staticity can be inferred automatically using the following rules:
1. A method (or property) should be marked as static if and only if its uses only compose of its parameters and/or static fields, provided it does not override a base method/property.
2. A field should be marked as static if and only if it is never accessed through an instance.
There are advantages and disadvantages to the inference approach:
Advantages:
1. No need to specify static explicitly, which may simplify work when refactoring code.
2. Code noise is reduced.
3. Accidental omission of static for methods is catered for, speeding up method access (refer to Performance of using static methods vs instantiating the class containing the methods).
Disadvantages:
1. If the code is not devised clearly, the code may be harder to understand. Proper code structure should be maintained. Also, method names should clearly represent the intention of whether the method should be static or not.
2. Compiler errors and warnings would have to be more clear, showing clearly what caused staticity inference conclusion to change, if present.
3. For libraries, static should still be programmatically specified, in order to make sure that deviation from the original usage intention is not permitted, unless stated otherwise...
If a library was to allow static to be inferred, then the compiler would omit specification in the object code, and the compiler/interpreter of the executable has to infer them by analyzing the code of itself and the referenced assemblies, generating staticity specifications to any fields, methods or properties that lack it.
Static classes are really easy to infer. A class can only be static if and only if it only contains static fields, methods and/or properties.
The question is: Why is automatic staticity inference not implemented in any popular language, not even optionally?
I think there are various situations that would benefit from such a feature.
Yours truly
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MathuSum Mut wrote: The following only for programming languages that compile libraries to object code and not native assembly code:
That has nothing to do with this.
MathuSum Mut wrote: Why is automatic staticity inference not implemented in any popular language, not even optionally?
Just guessing of course.
First the compiler must determine correctness anyways. So it must determine if the class is static so no point in throwing that information away.
Second since the information exists at runtime the system might as well use it. If the runtime environment supports verification then it might verify that the class is static, but if it does that then it has already derived that information and thus the system should keep it rather than throwing it away (thus requiring a re-derivation later.)
MathuSum Mut wrote: I think there are various situations that would benefit from such a feature.
Like?
Once the program is actually running everything should be resolved anyways. Yes, I understand that dynamic resolution might defer resolution but that just means it is in not fact running yet. After resolution it must be resolved so there is no reason to need it then.
During resolution, however that is done, the information is only needed to correctly resolve calling semantics. (Again ignoring something like a verification stage.) So if the information already existed, which it must for the compiler to correctly issue errors, then it might as well be maintained. It isn't like the space used to keep the flag would be a problem.
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The company i work for is looking for changing the architecture we work with. Now we have one main application that does everything. We would like to change that to small applications to do smaller parts of work. These applications are in different languages (c#, java, erlang, progress, ...) We are also looking at IoT and we have some older applications written in basic. What i would like to know is if anyone has any experience in esb's so al of these applications can communicate with each other. Our main language of programming of our own services and applications are written in c#.
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I see a lot of buzz words and no actual business reasons.
Sounds like a developer read a single web article and decided that re-architecting the entire enterprise was the way to go.
Tom Wauters wrote: What i would like to know is if anyone has any experience in esb's
Certainly one would hope that the internet bloggers who push it as well as selling their own expertise as consultants doing exactly that would have actually done that. But your mileage my differ if you look to one of them (of course their bank account would appreciate it.)
But other than that is there a question?
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