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.
I am looking out for developing a C# application which posts message to a ebMS3 platform using AS4. I am new to this area. Could anyone please help? Is there any third party libraries to do this easily? If not, how we post messages using AS4 from a c# solution.
I have just implemented our own AS4 solution, and it is hard task to accomplish. Especially because .NET does not support SOAP with attachments out of the box. And there is a lot background knowledge you need to know about - all the different specifications AS4 is based on. I have not been able to find an AS4 API written in .NET without it being a standalone solution as well...
First thing is to understand AS4, and a good place to start is this blog:
https://www.codit.eu/blog/2016/02/03/as4-for-dummies-part-ii-messaging-overview/
And then you will have to understand most of the EBMS3 specification:
http://docs.oasis-open.org/ebxml-msg/ebms/v3.0/core/ebms_core-3.0-spec.html
That being said - it is not impossible.
I have been looking at the AS4.NET framework as Sander talks about, and it is well-written and a very good starting point for exchanging AS4 messages. I have used it as a test-endpoint.
So unless you need to incorporate AS4 directly into an existing product (which we needed to), I can only recommend using AS4.NET.
AS4.NET is also open source (and e-SENS profile conformant), so you can have a look at their code-base and let you inspire by the hard parts in AS4.
For the MIME parts I can recommend Mimekit: https://github.com/jstedfast/MimeKit
And for some of the encryption/signing stuff Bouncycastle is great: http://www.bouncycastle.org/csharp/
Not sure whether it can be used as a library, but for a project within the European Commission an open source .NET based AS4 implementation was developed. You can find it here in the EC's code repository. I don't know if there is any support on this, so if that is important you should probably consider another implementation. A list of solutions tested by the EC for conformance with their own profile of AS4 is available here (or if that link doesn't work by searching for "as4 conformance tested implementations")
Note that most are standalone applications which you connect to for executing the AS4 message exchange. Most offer different integration options, so you should be able to integrate it into your solution.
I'm looking at Script#, JSIL and SharpKit as a tool to use to compile C# to Javascript, so I can program the client side functions of AJAX using C# in Visual Studio.
What are the pros and cons of each JSIL, Script# and SharpKit?
My project is a MVC4 project using razor engine and C#, if it matters.
If you're looking to integrate directly with an MVC project, something like Script# or SharpKit or something is probably your best bet - I know for a fact that Script# has stuff built in to make that sort of integration easier, so I would start there.
If you do want to try using JSIL, it probably has the core features you need, but things that you might want - like visual studio integration, automated deployment, etc - are not there. At present it is primarily targeted at cross-compilation of applications, so it does a good job of that but not as good a job of other use cases.
I'll try to give a summary of reasons why you might want to consider JSIL over those other alternatives - I can't really comment on the pros and cons of those alternatives in depth since I haven't used them:
JSIL has extremely wide support for the features available in C# 4. Notable ones (either because other tools don't support them, or they're complicated) include:
dynamic, yield, Structs, ref / out, Delegates, Generics, Nullables, Interfaces, and Enums.
Some of the above, of course, don't have complete support - to get an idea of things that absolutely will work, you can look at the test cases - each one is a small self-contained .cs file that is tested to ensure that JSIL and native C# produce the same output.
The reason for this extensive support is that my goal is for JSIL to enable you to translate a completely unmodified C# application to working JS. For all the demos up on the JSIL site, this is true, and I have a few nearly finished ports of larger real games in the wings for which this is also true.
Another reason is that JSIL makes it relatively straightforward for your C# and your JavaScript to talk.
All your C# types and methods are exposed via an interface that is as javascript-friendly as possible. The JS versions have basic overload resolution and dispatch so that native C# interfaces are callable from script code as if they were native JS in most cases. You don't have to take any steps to specifically tag methods you wish to expose to JS, or give them special names, or anything like that unless you want to.
When you want to call out from C# to JS, you can do it a few ways:
JSIL.Verbatim.Expression lets you insert raw javascript directly into the translated version of a function.
JSIL.Builtins.Global can be combined with dynamic and var to write JavaScript-like code directly in your C# function bodies.
The JSReplacement attribute can be used to replace invocations of a C# function with a parameterized JavaScript expression.
All of the above features can be combined with JSIL's mechanism for altering type information, called Proxies, to allow you to alter the type information of libraries you use, even if you don't have source code, in order to map their methods to JavaScript you've written.
And finally, C# methods that aren't translated to JS produce an empty method called an External that you can then replace with JavaScript at runtime to make it work again. Any External methods that you haven't replaced produce clear warning message at runtimes so you know what's missing.
JSIL makes aggressive use of type information, along with metadata you provide, to try and safely optimize the JavaScript it generates for you. In some cases this can produce better equivalent JavaScript than you would have written by hand - the main area where this is true at present is code that uses structs, but it also can apply in other cases.
For example, in this code snippet, JSIL is able to statically determine that despite the number of struct copies implied by the code, none of the copies are actually necessary for the code to behave correctly. The resulting JavaScript ends up not having any unnecessary copies, so it runs much faster than what you'd get if you naively translated the semantics of the original C#. This is a nice middle ground between writing the naive struct-based thing (Vector2s everywhere!) and going completely nuts with named return value optimization by hand, which, as I've described in the past, is pretty error-prone.
Okay, now for some downsides. Don't consider this list exhaustive:
Large portions of the .NET BCL don't have implementations provided for you by JSIL. In the future this may be addressed by translating the entire Mono mscorlib to JavaScript, but I don't have that working well enough to advocate it as an immediate solution. (This is fine for games so far, since they don't use much of the BCL.) This issue is primarily due to the IP problems related to translating Microsoft's mscorlib - if I could do that legally, I'd be doing it right now - it worked the last time I tested it.
As mentioned above, no visual studio integration. JSIL is pretty easy to use - you can feed it a .sln file to get a bunch of .js outputs automatically, and configure it automatically with a configuration file next to the project - but it's nowhere near as polished or integrated as say, Script#.
No vendor or support staff. If you want a bug fixed yesterday or you're having issues, I'm pretty much your only bet at present (though there are a few prolific contributors helping make things better, and more are always welcome!)
JavaScript performance is a goddamn labyrinth full of invisible land mines. If you just want apps to work, you probably won't have any issues here, but if like me you're trying to make real games run fast in browsers, JavaScript will make your life hell and in some cases JSIL will make it worse. The only good thing I can say here is that I'm working on it. :)
JavaScript minifiers and optimizers like Closure are explicitly not supported, because they require your code generator to jump through a bunch of hoops. I could see this being a real blocker depending on how you intend to use your code.
The static analyzer is still kind of fragile and there are still gaps in the language support. Each big application I port using JSIL usually reveals one or two bugs in JSIL - not huge game breakers, but ones that definitely break a feature or make things run slow.
Hope this information is helpful! Thanks for your interest.
Script# pros:
Free
Open source
Generates clean JavaScript
Script# cons:
Supports a subset of C# 2.0 language only
Can be compiled only in a separate project, cannot mix / re-use code between client and server
Low frequency of version updates
Does not offer support
Limited 3rd party library support, C# API is different than JavaScript API.
Not open source
Debugging in JavaScript only
SharpKit pros:
Commercial product
Supports full C# 4.0 language
High frequency of version updates
Support is available
Client / server code can be mixed and re-used within the same project
Extensive 3rd party library support, maintained as open-source - C# API matches exactly to JavaScript API
Supports basic C# debugging for Chrome browsers
Generates clean JavaScript
SharpKit cons:
Has a free version with no time limit, but limited to small / open-source projects
Not open source (only libraries are open-source)
JSIL pros:
Free
Open-source
JSIL cons:
Converts from IL (intermediate language), not from C#, which means a lower abstraction layer since code is already low-level.
Complex generated JavaScript code - almost like IL, hard to read and debug
Answers to feedbacks:
Kevin: JSIL output is not bad, it's simply generated to achieve full .NET behavior, much like SharpKit's CLR mode. On the other hand, SharpKit supports native code generation, in which any native JavaScript code can be generated from C#, exactly as it would have written by hand.
Sample of SharpKit's clean generated JavaScript code:
http://sharpkit.net/Wiki/Using_SharpKit.wiki
Developer can choose to create more complex code generation and gain more features, like support for compile-time method overloads. When specified, SharpKit generates method suffixes to overloaded methods.
Script# requires .NET 4 in order to run, but it does not support full C# 4.0 syntax, like Generics, ref and out parameters, namespace aliases, etc...
Another alternative is WootzJs. Full Disclosure, I am its author.
WootzJs is open-source and strives to be a fairly lightweight cross-compiler that allows for all the major C# language features.
Notable Language Features Supported:
yield statements (generated as an efficient state machine)
async/await methods (generated as a state machine like the C# compiler)
ref and out parameters
expression trees
lambdas and delegates (with proper capturing of this)
generics support in both the compiler and the runtime (invalidly casting to T will throw a cast exception)
C# semantics (as opposed to Javascript semantics) for closed varaibles
It is implemented using Roslyn, which means it will be first in line to take
advantage of future language improvements, since those will now be implemented via Roslyn itself. It provides a custom version of mscorlib so you know exactly what library functionality is actually available to you in your scripts.
What Are its Downsides?
The Javascript is not intended to look "pretty". It is clearly machine generated, though individual methods should be easy to reason about by looking at them.
Because of its extensive support for core libraries and reflection, the generated output is not the smallest on the block. Minification should produce an ~100k JS file, but minification is not yet supported.
WootzJs unabashedly pollutes native types with functions to encapsulate behavior for those types that would only be found in C#. For example, all the methods of System.String are added to the native Javascript String type.
Little support for binding to 3rd-party Javascript libraries presently exist. (Currently only jQuery)
Comparisons with Other Cross-Compilers:
Script# is very stable and has extensive integration with 3rd party Javascript libraries. Furthermore, it has excellent Visual Studio integration, and it provides a custom implementation of mscorlib. This means that you know precisely what functionality has actually been implemented at the tooling level. If, for example, Console.Write() is not implemented, that method will not be available in your editor.
However, due to its custom parser, it is still stuck in C# 2.0 (without even the generics found in that version of C#). This means that the modern C# developer is giving up an enormous set of language features that most of us depend on without reservation -- particularly the aforementioned generics in addition to lambdas and LINQ. This makes Script# essentially a non-starter for many developers.
JSIL is an extremely impressive work that cross-compiles IL into Javascript. It is so robust it can easily handle the cross-compilation of large 3d video games. The downside is that because of its completeness the resultant Javascript files are enormous. If you just want mscorlib.dll and System.dll, it's about a 50MB download. Furthermore, this project is really not designed to be used in the context of a web application, and the amount of effort required to get started is a bit daunting.
This toolkit too implements a custom mscorlib, again allowing you to know what capabilities are available to you. However, it has poor Visual Studio integration, forcing you to create all the custom build steps necessary to invoke the compiler and copy the output to the desired location.
SharpKit: this commercial product strives to provide support for most of the C# 4.0 language features. It generally
succeeds and there's a decent chance this product will meet your needs. It is lightweight (small .JS files), supports modern C# language features (generics, LINQ, etc.) and is usually reliable. It also has a large number of bindings for 3rd party Javascript librarires. However, there are a surprising number of edge cases that you will invariably encounter that are not supported.
For example, the type system is shallow and does not support representing generics or arrays (i.e. typeof(Foo[]) == typeof(Bar[]), typeof(List<string>) == typeof(List<int>)). The support for reflection is limited, with various member types incapable of supporting attributes. Expression tree support is non-existent, and the yield implementation is inefficient (no state machine). Also, a custom mscorlib is not available, and script C# files and normal C# files are intermingled in your projects, forcing you to decorate each and every script file with a [JsType] attribute to distinguish them from normally compiled classes.
We have SharpKit for two years and I must say that's upgraded the way we write code.
The pros as I see them:
The code is much more structured - we can now developed infrastrcture just like we did in C# without "banging our heads" with prototype.
It is very easy to refactor
We can use Code Snippets which results in better productivity and less development time
You can control the way the JS is rendered (you have several modes to choose from).
We can debug our C# code in the browser (Currently supported on Chrome only, but still :->)
Great support! If you send them a query you get a response very fast.
Support a large number of libraries & easily extensible
The cons:
The documentation is a bit poor, however once you get a hang of it you'll boost your development.
Glad if this could help!
For ScriptSharp, this stackoverflow link could be of help.
What advantages can ScriptSharp bring to my tool kit?
If you have any SVN tool, please download a sample from https://github.com/kevingadd/JSIL, this is a working source code and can help you go miles.
I am creating libraries that I will use across Compact Framework, Silverlight, WP7 and the full .NET runtime. I am aware that the question around sharing between Compact Framework and full .NET, or between Silverlight and full .NET has been asked many times and I have been reading all the answers around that, however this situation is further complicated because I have to use VS2010 for Silverlight/WP7 and VS2008 for Compact Framework.
I therefore need to use multiple solutions along with multiple projects for this.
Is there a suggested "best-practice" approach for managing this, I am aware that I can create the multiple solutions/projects using add-file-as-link functionality to maintain the project, however this becomes a manual process open to error which I'd like to avoid.
Has anyone had any experience with automating the build of seperate frameworks, for example creating and maintaining a single .NET project, but having a custom build action which tweaks the solution and project files automatically and building several output assemblies for the different required frameworks. I am aware there is an added complications with making sure the correct references are generated.
Is there an existing framework that achieves this, I've had a search around but can't see anything. Alternatively is there an appetite for the creation of such a framework?
This session from PDC2010 might help:
http://blogs.microsoft.co.il/blogs/arik/archive/2010/10/31/pdc-2010-3-screen-coding-sharing-code-between-windows-phone-silverlight-and-net.aspx
Microsoft have announced that the Portable Library Project will be available H1 this year - so it should be available real soon - maybe at Mix?
Until then, the best advice seems to be to create a SL 3 class library project for most of your sharing - WP7, WPF, SL-Web, .Net desktop - but you'll then still need to do something special for WM6 (but for WM6 I still need to do lots of special things anyway - like it still insists on using VS2008!)
target state: Porting VB6 Code into C#, undertake the whole project with all conceivable processes that are involved.
What would be your approach if you do not have knowledge about the domain?
There is nearly any documentation, just legacy code (up to 100.000 - 300.000 lines of code and comments vb6 files that contain up to 14.000 lines of code) written in VB6.
Disclaimer: I work for Great Migrations
We rewrite large VB6/ASP/COM applications to .NET (primarily C#) for a living and we have developed a software analysis and reengineering tool to help us do it. This tool is essentially like a VB6/ASP/COM compiler and a decompiler that authors .NET codes. Of course since the VB6 platform is very different from .NET, a direct compile/decompile is not desirable or viable, so our tool has an "analyzer" that implements various code reengineering algorithms to deal with VB6-C# incompatibilities. There is also a programmable "author" that allows the migration team to prescribe rules for setting up .NET code files, restructuring the code, and doing things like replacing COM APIs and ActiveX controls with .NET classes -- depending on what the team needs or wants.
As a by product of compiling and analyzing the code our tool produces a model of the entire VB6/ASP/COM system being upgraded. This model can be used to produce extremely detailed reports about the internal structure of the system. These models can be used to help reverse-engineer the code -- if you know the right questions to ask and you would need to understand the problem domain to do a good job.
Of course once you have build-complete .NET, you can use the various analytics and code review tools that work off assemblies. Some versions of Visual Studio have these tools and there are open source tools such as FxCop, NDepends). There are also some fantastic dynamic analysis tools (EQUATEC Tracer) that I have used.
In the end though migration teams are going to very hard pressed to verify any unknown system. Even if you are staying on the same platform, you would unable to prove an application it is "correct" if you do not know how to run it and how to setup/enter expected inputs and find/verify expected outputs. We normally leave this to the customer!
If we are doing verification for the customer, we rely heavily on side-by-side testing to validate the new version of your system -- assuming we know how to run the legacy application we assume that given the same sets of inputs and usecases it should exhibit the same behaviors and produce the same results. I have heard this Approval Tests in unit testing circles.
I admit we also rely heavily on the knowledge that the VB6/COM code is a complete, detailed, formal and production tested description of the data structures and logic of the system and that we are putting this information through a tested and retested systematic transformation. We have been developing compilers since 1977 and we have worked very hard on this VB6/ASP compiler to make sure the .NET codes that we generate preserves the semantics of the original VB6. It is not 100% every time - but it is getting closer all the time. Then again doing things by hand does not guarantee 100% correct code on the first try either...
mark's answer about Great Migrations is excellent. Do be aware there are competitor automatic tools, which also have a very good reputation.
Artinsoft's VB Upgrade Companion
Francesco Balena's VB Migration Partner