Can you use namespaces in one program to get the classes from those other programs in your program? Or do you do this using assemblies? And how do you do it?
To use classes defined in another program (let us call this program an "assembly"), you can reference that assembly in your program/application and use the classes. The classes have to be defined as public in that other assembly.
An assembly is basically an .exe or a .dll, as explained in this answer.
Usually classes that are meant to be reused are defined in a class library and compiled to a .dll.
The goal of namespaces is to separate the code into meaningful pieces, as explained here.
A namespace creates a sort of "full name" for a class. So, in you program you will have to reference a class defined in another program/assembly by its full name, meaning using its namespace and its class name.
If you are trying to use code from one c# project in other you just need to add a reference in the project you are going to consume the code to the project with the code to be consumed.
If you are trying to consume code from an already compiled assembly and this compiled assembly is .net you can either use reflection or .net decompiler to get the code.
Jetbrains have a .net decompiler.
I have a solution with many F# and C# projects. My goal is to merge them all to one library using ILMerge. Resulting merged dll will be put in a NuGet package and referenced in other projects. However, I'm running into few issues when merged dll is referenced in F# projects.
The problem I have is that if primary assembly given to ILMerge is F# then referencing resulting dll in F# project allows to only access F# types. If C# dll is chosen as primary assembly for merge then extension methods from merged F# assemblies were not available when referencing in F# project. Also modules with AutoOpen attribute were no longer implicitly opened when opening enclosing namespace.
Is there a way to merge F# and C# assemblies so that all types (including extension methods) would be available?
In part of our code base, a big chunk of the library is done in F# and the rest in C#. Both F# and C# code are front facing.
We have a hellish batch file to take care of mergeing and what I see is that we are merging with this code:
echo merging %mergeapp% /keyfile:"%keyfile%" /target:library /attr:"%dstpath%%csharpdll%" /targetplatform:%targetplatform%,%targetlib% /lib:%sllib% /lib:%targetlib% /lib:"%libpath%lib" /out:"%mergedpath%..\%csharpdll%" "%dstpath%%csharpdll%" "%dstpath%%fsharpdll%"
%mergeapp% /keyfile:"%keyfile%" /target:library /attr:"%dstpath%%csharpdll%" /targetplatform:%targetplatform%,%targetlib% /lib:%sllib% /lib:%targetlib% /lib:"%libpath%lib" /out:"%mergedpath%..\%csharpdll%" "%dstpath%%csharpdll%" "%dstpath%%fsharpdll%"
and that does what we intend. However, we do not publish any extension methods nor do we do any AutoOpen. What we discovered was a bug in the F# compiler that, up until we started putting obfuscation in the mix, required us to run ildasm on the F# assembly and rip out the offending code. The other issue is that F# doesn't properly support the protected modifier on members (F# makes them public) so we created an attribute that we could hang on class members that were meant to be protected. Then we wrote a tool that uses Cecil to blow the assembly apart, rip out our attribute and change the access to those members to protected (code is in the accepted answer here).
I didn't know about AutoOpen, but I had to do a similar task, so I created class called a registrant that did that kind of work like this:
type FSharpRegistrant() =
do
// do whatever I need to get going
Then in a static constructor within the C# module, I wrote some code that instantiates the F# registrant using reflection to find the class (since in my code base the C# code builds first and doesn't know there's F# code at all). This is ugly code with a lot of error checking, but it works.
I am using IKVM to wrap a java application into a dll. I am not particularly familiar with IKVM so I apologize in advance for not providing enough information. Anyway, I am using a c# library that makes a call to a dll created by IKVM. However the library I am using appears to require both IKVM.OpenJDK.ClassLibrary and IKVM.OpenJDK.Core. The only problem is both of these libraries contain java.util, which causes a namespace ambiguity for any class in java.util (Vectors, hastables, etc). I cannot fine a way to reference all instances of objects found in the java.utils class to explicitly use either ClassLibrary or Core. Is there anyway to reference a namespace to instruct my library to use one or the other for java.util calls?
In the current version of IKVM there is no IKVM.OpenJDK.ClassLibrary. It look like that you mix different versions of IKVM.
I am working on C# for a few mounths. Mainly I am working on C++.
On C++ using the visual studio if I wanted to add a a static library I could add it using the configuration of the project add the header and lib and path.
When using C#, I think it is something like DLL, all those assemblies are complied on late binding ?
In addition using the visual studio for the C# I can add a reference. Is this the equel thing as I wrote in the beginning of the question ? only for something like DLL ?
If your want use a Win32 DLL in C#, you must write a C# wrapper for it.
C# is managed, and everything you reference as an assembly gets linked at runtime, as with DLL's in C++. The compiler will check at compile time that you are using your assemblies properly, but it wont link them yet. You can use http://research.microsoft.com/en-us/people/mbarnett/ILMerge.aspx to merge assemblies together, as a post-build step.
I am developing a GUI based application in MS Visual Studio 2005, I just want to
know if it is possible to use both VB.NET and C# in the same project. Or can I include a module written in C# in my VB.NET project?
I have a class written in C# which I want to use in my VB.NET based project, so if I can include and call functions from that project than I won't have to write the class again in VB.NET.
So please help me as I am new to .NET programming.
I just want to know that is it possible to use both VB and C# in the same project.
No, not in the same project. On the other hand, you can use them in the same solution.
Or can i include a module written in C# in my VB.net project.
I propose that you create a solution containing two projects: one in C# which forms a library that you use from your VB project. This is straightforward, easy to maintain and easy to extend.
I've never done it myself, but I know you can compile the C# code into a dll and then load and reference the dll in your VB project.
From "Calling C# class in VB.net":
I think the C# code that you want to
use must be compiled as a DLL. Once
that is done, simple add a reference
to that project to your VB.Net
project, import the namespace you
need, and then you can use the C#
code.
Also see How To: Create and Use C# DLLs (from MSDN, for VS2005)
You also want to ensure that you C# code is CLS compliant. This means that it won't publicly expose any functionality which other .NET languages won't understand (for example unsigned ints - which don't exist in VB, or differing classes only by case - since VB is not case-sensitive). To do this you need to add an attribute so that the compiler will raise errors if you have broken any of the guidelines. This article shows you how to do this:
The CLSCompliantAttribute can be applied to assemblies, modules,
types, and members.
For marking an entire assembly as CLS compliant the following syntax
is used
using System;
[assembly:CLSCompliant(true)]
For marking a particular method as CLS compliant the following syntax
is used
[CLSCompliant(true)]
public void MyMethod()`
Put VB.NET and C# code in separate projects. (I am using both VB.NET and C# in my open source project, http://msquant.sourceforge.net/, and it works great).
You don't need to worry about DLLs, just reference the project (use tab "Project" in the "Add Reference" dialog box). E.g. if you need to use a function in the C# code/project add a reference in the VB.NET project to the C# project.
You can't use a C# file and VB file in the same project. You can, however, have VB and C# projects in the same solution and reference them.
In your code you can use:
Imports namespace
or
using namespace
Once the reference has been added to the appropriate project build the solution and you are good to go.
You can also create a VB.NET Library in a separate solution, compile it and import the DLL into the C# Project or vice versa.
You must also know that if you have a VB.NET project with a C# project in the same solution with one of them having a reference to the other, changes apply in the referencing project will just be available to the other after rebuilding the solution. It's like having binary reference, but with the capability to change code on the same solution.
Personally, I don't like this, but I'm always in the situation where I modify the code in the referencing project and don't know why my changes are not in the code where I use it and I figure it out, oohhhh, I must rebuild.
For temporary help, it could be acceptable but not for programming every day.
If you were only planning on using the module in Visual Basic projects, then you should consider just converting the code to Visual Basic. If you need to use the module in both C# and VB.NET programs I would use one of the solutions posted above
You might try something like *Convert C# to VB.NET. It converts C# to VB.NET code. I use this page exclusively when I have to convert something I find on the net that was written in C#.