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Can I use .NET core with only F# or will I need to learn C# too?

F# has recently caught my eye as something I'd like to learn more about, but I have never used the .NET platform and know very little about it. If I want to write a small website in .NET core can I do that with only F# or will I need to expand my learnings to include C#?

You can definitely use .NET Core with pure F#. There is no C# knowledge required, though it can be beneficial to familiarize yourself with it enough to understand usage and library documentation.
The official Getting Started with F# guide has a section on using .NET Core with "just F#", which you can use as a starting point.
As for writing a website, I highly recommend looking at the SAFE Stack intro, docs, and samples. It shows how you can use only F# for full stack web development, all using .NET Core.

This depends on your learning and working style.
Technically, F# does not need any support from C#. You can write complete programs of any kind whatsoever without ever touching C#.
However, a lot of F# resources online are geared towards migrating from C# to F#, and as a result are phrased in terms of the differences between the two. Something like "you've been doing this thing in C# before, but here's how it can be done way better in F#".
Additionally, a lot of .NET libraries are written in C#. The binaries are, of course, completely compatible with F#, so you don't need to do any sort of special tricks to use C#-written libraries. However, if you ever want to look at the source code, that's where C# knowledge would come in handy.
To be fair, there is quite a large number of F#-exclusive libraries out there, but the majority of .NET libraries are still in C#. So chances are, you will end up using some of them. Whether you would actually want to look at their source - that depends on your style.

There are some libraries that I could never get working nicely in F#, so I tend to have some C# projects built into my solution to handle things that I just could not find an elegant way of doing in F# - like using the high level "Nest" Elasticsearch driver. It is designed to give you very elegant code in C# but I found it was the exact opposite in F#, sort of defeating the point of using a high level driver.
C# is nothing to fear though, it is readable and intuitive for the most part. I came into F# with no knowledge of .NET and have learned what I've needed as I've gone along without any troubles.

Android to WP7 absolute newbie question: C# or VB?

I'm going to migrate my Android application into WP7 platform. Android one contains heavy enough calculation stuff (encryption/decryption), plus extensive usage of DB (SQLite) and some graphics (simple) and I'm trying to figure which language to select: either C# or VB
I have some experience both in C# and VB.net, but can't decide which one to select, any clues?

I would recommend C#, based on a couple of factors:
I assume the Android application is written in Java. Between C# and VB, C# is the most similar.
If you are doing lots of calculations, C#'s more terse syntax will probably make the code easier to read. VB is more verbose and thus tends to produce more clutter.
Since you are new to the platform, you will definitely find a lot more resources with C# code examples than with VB.

I went from VB.net to C# and wouldn't ever go back through my own choice!
Aside from the technical differences (see here for just one comparison), it's my personal opinion that C# is more readable, fluent and just plain better.
Do a search on google for heaps of comparisons on why one is better than the other. At the end of the day it's your personal preference... try both and see which you prefer.

There are no technical benefits or drawbacks to choosing either language; the complete set of APIs and platform features are available to you whether you choose C# or VB.NET, so it comes down to whichever you are most comfortable with or want to spend more time with.
The only thing that might sway it one way or another is that (in my opinion) there are more samples, blog posts, and general help written in C# than VB.NET, but that's about the only differentiator I can think of.

If you aren't particularly familiar with either then definitely use C#. By far and way the vast majority of code you will come across in the Web and in books on Silverlight will be written C#.

I'd go with C#, it's a far more popular language. Furthermore, Java to C# is an easier transition.
Edit:
Popularity of a language make's it easier to find information and perhaps more importantly, quality developers.

Choose the language you are more comfortable with.

I would suggest c# because it's more similar to java. So maybe you will manage to save code structure.

C# for sure. C# is a lot more alike Java, and syntax alike much more compatible.
Next to that C# is more popular so more resources for it, and because of the extra time they spend on C# the compiler slightly generates higher performance MSIL.

If you know Java you'll find C# very comfortable to transition to and work with, especially if you're having to maintain older Java code as well as working on the new project. I've worked in situations where I had to work with VB6, VB.NET and C# code within the course of a day and it can be tricky to remember not to use or to use semi-colons or that the variable type goes first or last.

Planning a programming project by example (C# or C++)

I am in the last year of undergraduate degree and i am stumped by the lack of example in c++ and c# large project in my university. All the mini project and assignment are based on text based database, which is so inefficient, and console display and command, which is frustrating.
I want to develop a complete prototype of corporate software which deals in Inventory, Sales, Marketing, etc. Everything you would usually find in SAP. I am grateful if any of you could direct me to a books or article or sample program.
Some of the question are :
How to plan for this kind of programming? should i use the concept of 1 object(such as inventory) have its own process and program and have an integrator sit for all the program, or should i integrate it in 1 big program?
How to build and address a database? i have little bit knowledge in database and i know SQL but i never address database in a program before. Database are table, and how do you suppose to represent a table in a OOP way?
For development type, which is better PHP and C++ or C# and ASP.NET? I am planning to use Web Interface to set form and information, but using a background program to handle the compute. .NET is very much integrated and coding should be much faster, but i really wonder about performance if compared to PHP and C++ package
thank you for the info

This may not answer your question directly, but I thought this might help you get started in some way. So here it goes: I would say, "think through the process". This means, think through the software development process:
Gather requirements
Identify and define the problem.
Get as much information/facts as you can. (turn on green light, think about everything that you want to go into your software)
Come up with a baseline (turn on red lights, what you really want? the minimum functionality your software "must have" - cant live without)
Analyze
Know what you don’t know, what are the missing facts?
Evaluate your information or lack of it/reliability of information source.
Infer facts that you don’t know.
Form an assumption, opinion, or possible solutions.
Consider alternatives and implications of each solution.
Form an action plan.
Identify technology pros/cons.
Decide technology
Comeup with a functional specs.
Research
Dig into stuff that you would want to know (Best database, ORM, design practices, code samples - gather everything, read about inventory systems that are already there)
Design
Develop
Test
Fix
Prepare deployment plan
Release the product
Gather user feedback
Analyze user feedback
Plan for items in next release.
Repeat steps
And Enjoy!

Before I start this is a shallow answer to a deep question.
1) It looks like you have a reasonable grasp of the major components of your target application. As a .net developer I'd build assemblies that matched broad areas of functionality (not sure what the equivalent is in PHP) and then you can use those assemblies together as a single large app, or seperately as required. It's unlikely you'll get it right first time, so build it how it feels right, and then do some ruthless refactoring to make it better once you've got a handled on the problem.
2) This whole area is covered by Object Relational Mapping - ORM, NHibernate is the best of the bunch in the .Net world. BTW if you learn that you'll be way ahead of the game come graduation/work time. Raw sql is so last decade. I guess you know that Sql Server Express is a free download?
3) For development go with the languages/environment you feel most comfortable in. My preference is .net, and the integrated coding is much faster. Performance is definitely good enough, especially as this is learning project - SO runs on .Net and that supports a gazillion users pretty well.
Enjoy

I don't have any good recommendations for SAP-like projects in particular, but in general the best examples to use for things like this are well-established open-source projects. Anything else is going to be a "toy" example in one way or the other, and will be simplified and cleaned up. It's the "cleaned up" that makes it most unrealistic -- one of the really key things that makes real-world large software projects different from university examples is that the real world is messy, and real-world requirements are messy, and collaboration between lots of people with not quite the same priorities is messy, and real-world software projects have to adapt to and thrive in this messiness.
In answer to your specific questions, though:
1.) Do things in a modular way. This means you have something you can test and work with as soon as you get the first module done. That's especially important when you're learning, because (a) you probably won't have time to actually finish the whole thing, (b) you'll learn a lot from writing the first bit that you'll want to apply in future bits and then you'll probably want to rewrite the first bit, and (c) you'll learn even more from using the first bit.
2.) There are many views on this, and many online articles and books. I can't answer that in an answer here (except to note that in some cases trying to represent it in an OOP way is the wrong programming paradigm -- be careful about overconstraining the answer by the question you ask!); the right answer is to find things to read and spend some days reading them.
3.) You do not care about that sort of performance issue here. Successful programs have been written in both forms. You care about what will teach you the most, and what you are comfortable working with. Either one should be fine. You'll probably find more open-source pieces to look at with PHP and C++.

Your question pretty much covers the whole gamut of planning for a project; a whole thesis might be written (+:
Keep in mind what your team and your teaching-staff want out of the project.
1) Modular is my choice. It'll force you to address the application one module at a time and keep you focussed, but that is subject to
The familiarity of your team with the preferred/recommended language for this project.
Time in hand
Remember that modular means you will necessarily have to provide for module integration too.
2) C++ or C# ? Whichever offers the more learning experience. My own experience with both mentioned technologies is limited, but I remember there used to be a Database Template Library (DTL). C# on the other hand will probably be faster to develop. I could be wrong. There are any number of free DBMS engines available on the net. Unless the assignment explicitly recommends using a text, opt for one of these.
3) I concur w/Brooks up there ^^^
Good Luck!

You are a university undergraduate. And you are talking about complete inventory system.
I suggest building a blog application first with all the best practices (like blogengine), then move to e-commerece sites (nopcommerce, dotcommerce). And then do whatever you like.
This is a common problem with undergrads like you, of jumping way higher without building any simple projects first.

As a full time PHP developer, PHP sucks! ASP.net is okay (mmm... no it sucks too), but it locks you into proprietary licenses.
If you're starting from scratch, go for node.js. It's c++ and server-side javascript. Yes, it's new, but it has engineering promise. It'll be more commonplace in a few years.
And if you're worried about performance, don't. Javascript in V8 is extremely fast.
http://shootout.alioth.debian.org/u32/which-programming-languages-are-fastest.php
Here are some node.js links to get you started:
http://www.delicious.com/homer6/nodejs
Enjoy.

Migrating a project from C# to Java

With some changes in the staffing at the office, the levels of C# expertise has dropped off precipitously and there are now more Java developers. It has gotten to the point where the higher-ups are considering moving an existing .NET project written in C# into the Java world.
Aside from the obvious problem of starting completely from scratch what are the possible ways that this company can accomplish a successful move of development on a project from .NET C# into Java?

Here are things to consider:
Is this big project? If Yes, try to stick with C#
Is this medium sized project with components? If No, try to stick with C#
Is this small project meant to be deployed on windows only? If yes, try to stick with C#
Is this old source code? If Yes, try to stick with C#
Do you use windows OS specific APIs? If Yes, try to stick with C#
Do you use any third party APIs without Java counterpart? If Yes, try to stick with C#
Do you use .Net in "deep"(data binding, User controls etc.)? If yes, try to stick with C#
Migration time is more acceptable than getting new/converted C# guys? If no, try to stick with C#
Do you think end users will not be receptive of changes, if you are to use Java framework which will change presentation? If yes, try to stick with C#
Check commercials
If you decide to convert:
Go per component
Go per layer
Have lots of tests
Check if there are tools to help (however small help may be) with migration

Just to add to Brian and Eric's opinions, I would say that picking up C# for a Java developer should be straightforward in my opinion. They are conceptually very similar languages and I would suggest training your Java developers to gain some C# skills so you won't be forced to go to the hassle of a migration process.

I subscribe to Joel's view that a total rewrite is almost always a mistake. Other posters are right: C# and Java are similar enough that any competent Java developer should be able to become competent in C# in a matter of weeks or months. That's not to say they will be experts. That takes longer but as long as you have some C# developers who can guide the process then you should be OK.
It's hard to comment on whether or not such a transition is a good or bad idea without knowing specifics of your application: size, type of application, industry and so on.
I would be extremely reticent about such a switch because, in my humble opinion, C# is now a much more modern language than Java and I say this to you as someone who has been a Java developer ofr over a decade (since the 1.0.2/1.1 days).
That's not to say that Java is bad. It's not. Sun does have a cloud hanging over it and demonstrated an unwillingness or inability to drive the platform forward in recent years.

Regardless of the languages involved, the management of this company sounds insane. For anything other than a trivial application, how can it be economically sensible to rewrite an entire code base from scratch instead of just hiring a single person with some skills in the right language? Is this a business with that well-known problem: too much spare cash?!
How long has the existing code been in development? If it's barely started, I could understand this. If it's seen a release and has active users, it will never make sense to throw it away. If you donated the C# code to a start-up with the right skills, think how much of a head start they would have over you.

Before you finish converting the .NET project into Java, all those Java developers who were part of the conversion project will have learned C#. So then you don't anymore need to convert it to Java (and you can throw away all Java code which was produced in the conversion), because now you have a development team which can do both Java and C#. Problem solved. :D

Have a look at Net2Java, which puports to assist in converting your code from C# to Java. I doubt it'll be perfect, but its one way to remove a lot of drudgery from the task, leaving you with the kinks of incompatible framework calls and language features to iron out.
Once you've done that, your task is like any other large migration project - test, test and test again. Unit tests, System integration tests, then end-user tests. You should havew those tests already in place that you used with the original application, apart from the unit tests, they will still be relevant.

If there are any components that are already isolated or any of it uses a service-oriented architecture, you could conceivably migrate one component at a time (where each individual component is a rewrite) and still have the components talk to one another using the same interoperable network protocols. Probably depends on what type of app we're talking about.

Make sure you have tons of tests, because such a migration will bite you where you expect it least.

Do you have more .Net or more Java applications in production. If your already have a substantial investment in .Net servers and applications, why not ask for volunteers among the Java developers to move to .Net? The language and syntax is very similar, so the hard part would be learning the framework and unless they would spend all their time doing UI development even learning the framework is not that hard.
In our office we have a number of very good developers who move back and forth between Java and .Net as needed.

I am not a Java expert, but from my experience working with Java code whilst being a C# fan, the following are some of the possible headaches:
Generics are implemented differently in Java and C#.
Boxing/Unboxing behaviors are different between Java and C#
Java class naming convention + lots C# generated code
String handling (i.e. Unicode/ASCII concerns) can be problematic depending on the quality of Java/C# code being ported over.
Personally, I don't think writing from scratch is a bad idea at all. Since you already have a working architecture.

In order to prove to management, you always needs to talk in terms of ROI and numbers. Show them that if you move these applications, it will take tremendous amount of time, QA resources, and can easily take a back seat if it gets de-prioritized due to some other project or new development taking importance.
I had success when I showed them the timelines, ROI, work involved, money involved, etc.
So now coming to the actual point, I do think Java developers would be able to support C# unless they have some fundamental mental block against Microsoft technolgies.

Possibly you could use jni4net - opensource bridge ?
Or list of other options I know.

I'm somewhat surprised noone even suggested the idea of rejecting migration.
I do not believe a C# developer can be forced to switch to Java (or vice versa) because he was told to (well, if he's threatened with a gun then maybe). I takes much time, exercise and passion to master at least one technology stack. You just can't start overnight with a new technology and expect to provide the same quality.
I'd personally not bother until told to start migration. At which point I'd tell the manager that I'm .NET guy and won't switch to another technology just because they decided to.
As for the technical side, it's not the language syntax that differs but rather libraries and their features. Of course, if all the latest bells and whistles of .NET 3.5 have been extensively in use then the language difference will provide you with a real challenge.
That's certainly a funny way, just decide to migrate applications from .NET to Java. Someone has no idea of the hassle involved...

I realize that this is an old question but to anyone else going down this path, you could try this open source C# to Java Converter:
http://www.cs2j.com/

Program with C# front-end and Java back-end: Good or Bad Practice?

My friend and I are having a disagreement over an application development issue. It's a simple production management application.
According to my friend, the front-end stores data in XML, and a Java program will read the XML document, store it (at the back-end), and apply some business logic and again store the results into another XML document. And a C# front-end will display the result ( He wants to use sockets for communicating the status of XML ).
I think this is a bad idea. I suggested that whole application should either be written in C# or in Java.
Note: The application is standalone. It's not used over a network.
Have any of you tried this? Please share your thoughts :)

You're right and your friend gave a bad idea. In addition, from your question, I see there are several troubled issues, I don't know where to begin so I will just list them but not in any particular oder. But the ground rule for you to read on is you must agree that simpler is better as Einstein said "Things should be made as simple as possible but not simpler" (or something like that, I don't remember the exact quote).
The notion of front end and back end do not really apply to a desktop application. Rather, you want to use the MVC pattern for the separation of concerns. Wikipedia might be a good place to start learning or reviewing.
Why use of socket (which is totally unnecessary) if you don't have to. This is the first reason why it's a bad idea as you would not need using sockets if everything is done in language, running in the same process space (Your app is a desktop or standalone app).
Similarly, why XML (again unnecessary). No need because you can just pass Java or C# objects around. With XML, first there is the signal to noise issue as tags are added to the true data. Then there is the time to parse, to construct the XML, additional libraries potentially, etc. Thid would be all that code which are introduced in your friend's approach.
These are the most obvious reasons. There are other reasons from a manager's or company's perspective:
To maintain this application, the manager or company needs to hire 2 different skillsets. This might not be true as most programmers are multilingual anyway. But that's not always the case.
In term of deployment, now you force your users to have both the JRE and the .NET framework installed just to be able to run your application. And either of those is not exactly a small footprint.

Talk about making it complex. Either Java or C#. One really isn't a backend for another. They both 'do the same things' as languages. The only difference is whether you want to leverage the power of .NET, or the power of the immensely huge Java frameworks.

This is a desktop application that "is not used over a network"... I'm failing to see a need for a real "backend" at all.
Write the desktop application in a single language, and store your data in XML.

So your application is standalone and doesn't need to work over a network, but your friend insists on connecting the front and back ends of the app using sockets? Something is wrong with this setup, seems more complicated than it needs to be.
It sounds to me like your friend wants to use Java because he understands Java's XML handling framework better. Personally, I think interop between Java and .NET is overkill. You'll save yourself a lot of man hours and frustration by writing the app in a single language of your choice.

What your friend is suggesting is to keep things modular. It doesn't really matter what language you use, but if throw it together in one big project you might make it non modular.

For that type of app I would use one only one language.

It may be possible to leverage the power of C# desktop app on the front-end and Use Java Ejb+Web Service (Jax-ws) on the backend. C# apps can read SOAP wsdl to create the stubs and the interfaces to access Java backend implemented by Jax-ws.