Here are the steps what I have done.
I have created a .dll file using C# with the content as
public static int MyFunction(int dummy)
{
MessageBox.Show("I am in dll");
return 0;
}
I have also created an MFC application (exe) with content as
int main()
{
int a = MyFunction(0);
return 0;
}
Is this right way to do the call ?
Note:
i. I have changed my MFC application to /cl (common language run time support)
ii. I have also added C# file in the MFC's Reference.
Problems I faced:
Error 1 error C3861: 'MyFunction': identifier not found
Warning 2 warning C4793: 'MyDialog::`vcall'{132}'' : function compiled as native :
I have used the following command in the MyDialog.cpp file as a last line, the warning is solved.
#pragma unmanaged
Now how to solve the Error?
The C# code is placed inside a class, say MyClass. If you want to call a static member of this class in C++/CLI, you need to use MyClass::MyFunction(0).
Finally, you would need to add the namespace: MyNamespace::MyClass::MyFunction(0).
You can compile your C++ program with the /clr flag and use C++/CLI to simply call any .NET code (as long as you include a reference to it).
You could also use a COM callable wrapper for your C# code (compiled in a DLL) -> check this article
Related
Function calls from Java to C# through JNI-C++/CLI are failing when the C# COM is not registered using regasm with the codebase option. I've built a sample following the instructions in P2: Calling C# from Java with some changes.
Numero uno: C#
Change the C# dll into a COM by creating an interface, IRunner, and making the library assembly COM-visible.
namespace RunnerCOM
{
public interface IRunner
{
String ping();
}
public class Runner:IRunner
{
static void Main(string[] args)
{
}
public Runner() { }
public String ping()
{
return "Alive (C#)";
}
}
}
Numero due: Java
No changes made to the Java section.
Numero tre: C++
This part was changed to create a new instance of the RunnerCOM.Runner class and use that result. Here is a good tutorial on how to call managed code from unmanaged code: http://support.microsoft.com/kb/828736
#include "stdafx.h"
#include "Runner.h"
#pragma once
#using <mscorlib.dll>
#import "RunnerCOM.tlb"
JNIEXPORT jstring JNICALL Java_Runner_ping(JNIEnv *env, jobject obj){
RunnerCOM::IRunnerPtr t = RunnerCOM::IRunnerPtr("RunnerCOM.Runner");
BSTR ping = t->ping();
_bstr_t temp(ping, true);
char cap[128];
for(unsigned int i=0;i<temp.length();i++){
cap[i] = (char)ping[i];
}
return env->NewStringUTF(cap);
}
Now to my questions,
The code above fails with a _com_error exception, Class not registered (0x80040154) unless the codebase option is enabled during regsitration of RunnerCOM.dll, with regasm.exe. Why is this? If the code is not ran from JNI, I tested it as an exe, it works fine. The RunnerCOM.dll is simply found in the working directory.
Type casting _bstr_t temp to char* fails. For example, char *out = (char*) temp; Similar to the issue above, it works fine when it's built and executed as an exe but crashes the JVM when it's a JNI call.
By the way this is what I used to run it as an executable:
int main(){
RunnerCOM::IRunnerPtr t = RunnerCOM::IRunnerPtr("RunnerCOM.Runner");
BSTR ping = t->ping();
_bstr_t temp(ping, false);
printf(temp);
return 0;
}
Codebase creates a Codebase entry in the registry. The Codebase entry specifies the file path for an assembly that is not installed in the global assembly cache, so when you specify the codebase, the system will find the DLL based on the path. If not, it will try to locate the dll in the GAC and current working directory. In JNI, I think the current working directory is not the folder where the DLL is. You can use process explorer to find what is the current working directory, also, you can use process monitor to find out which directories the exe is looking into to find the dll.
The code converting _bstr_t to char*, the char* string cap is not ended with '\0', I think this might cause problem in JNI. Uses the _bstr_t operator (char *), you can obtain a null terminated string from the _bstr_t object. Please check the msdn example for details.
You mentioned C++/CLI, C++/Cli and COM warpper are two different ways to interop with C# code. If you're using C++/CLI as a bridge, you doesn't need to register C# DLL as COM, please see this: Calling .Net Dlls from Java code without using regasm.
If you're using COM, you should call CoInitialize() to init COM first in your code.
I tried to call the function from .dll file using java native interface ,its successfully working, But I don't know how to call function from .dll using C# ,please advice me on this.
Look at DLLImport attribute in MSDN
http://msdn.microsoft.com/en-us/library/aa664436(v=vs.71).aspx
using System;
using System.Runtime.InteropServices;
class Example
{
[DllImport("your_dll_here.dll")]
static extern int SomeFuncion1(int parm);
static void Main()
{
int result = SomeFunction1(10);
}
}
If it's a native DLL, you need to add a DLLImport statement, importing the function you want.
The documentation is here.
The attribute looks like this, typically:
[DllImport("YourDllNameHere.dll")]
public static extern int YourFunction(int input);
This will import a function called YourFunction (which takes an int input, and returns an int) from YourDllNameHere.dll.
Let's say your DLL name is MyLibrary and MyFunction is the function contain in your DLL .
First right click on your Reference , browse and add your DLL .
Declare your DLL as a namespace using MyLibrary;
And you can call MyFunction !
Or
Another way ,
you can use this msdn reference !
Add that dll into your project as a referenced dll into reference folder(right click on references ,add reference then "Browse" to you DLL).then it should be available for to use as you want and just use that dll as follows in the code level.
using System;
using YourDllName;
class ExampleClass
{
//you can use your dll functions
}
I like the link provided by Baldrick for DllImport attribute.
This is what I recommend.
Download Dependency Walker (small application exe, no need to install).
Open your DLL in the Dependecy Walker to view the exposed entry points of DLL.
Declare external call to native function in C# like this.
C#:
[DllImport("Your_DLL.DLL", EntryPoint="Function_Entry_Point",CallingConvention=CallingConvention.StdCall)]
static extern IntPtr Function1();
Note:
If entry point is not specified the function name is considered as the entry point.
When you run the application make sure the native DLL is in the
same folder.
First off, I'll admit I'm cargo-culting this a little bit -- my nice clean sample code doesn't work when I'm wedging it into the real world. That being said...
I have a DLL called CPierce.CSharpCall.dll that has something like the following C# in it:
namespace CPierce.CSharpBridge
{
[System.Runtime.InteropServices.Guid("3D08DF02-EFBA-4A65-AD84-B08ADEADBEEF")]
public interface ICSide
{
// interface definition omitted...
}
[System.Runtime.InteropServices.Guid("CBC04D81-398B-4B03-A3D1-C6D5DEADBEEF")]
public partial class CSide : ICSide
{
// class definition omitted...
}
}
This is registered with regasm /tlb, etc.. Then, my C++ code looks something like this:
#import "CPierce.CSharpCall.tlb" named_guids
// Contains syntax errors!
int myfunc()
{
HRESULT hRes = S_OK;
CoInitialize(NULL);
CPierce.CSharpBridge::ICSide *pManagedInterface = NULL;
hRes = CoCreateInstance(
CPierce.CSharpBridge::CLSID_Class1,
NULL, CLSCTX_INPROC_SERVER,
CPierce.CSharpBridge::ICSide,
reinterpret_cast<void**> (&pManagedInterface));
// Calls to the interface omitted....
CoUninitialize();
return 0;
}
The problem is, of course, the syntactically wrong bit about CPierce.CSharpBridge. I know in C++ if I want to have a similar namespace to the C# code I could say:
namespace CPierce
{
namespace CSharpBridge
{
// definitions go here
}
}
But I don't think that's what I'm looking for here, since I just need to refer to two constants that are in another namespace without putting the entire method in that namespace.
What is the C++ syntax I need to complete this call to CoCreateInstance?
Update: On deeper (much deeper) inspection, I'm finding that my .tlb file created by regasm is nearly empty. When I catenated all of my source into a single .cs file and compile with:
csc /debug /t:library BigFile.cs
regasm BigFile.dll /tlb:BigFile.tlb
I get a hefty (and useful) tlb file.
When I compile the whole project from Visual Studio, I'm getting a .DLL all right, but regasm doesn't do anything with it but produce a minimal .tlb file. (ildasm shows almost no differences between the two DLL's)
If I compile BigFile.cs in Visual Studio, I get a DLL that's also useless.
I'm stumped.
C++ doesn't use the . operator to delimit namespaces; it uses ::. You would use CPierce::CSharpBridge instead of CPierce.CSharpBridge. Unfortunately, that doesn't seem to help you because you don't know what namespace is actually being generated by the TLB.
A simple solution to that is to not use namespaces at all and import without them:
#import "CPierce.CSharpCall.tlb" named_guids no_namespace
This appears to be a problem on the C#/Visual Studio side. I'll abandon this question and open an appropriate one. Thank you for your help in narrowing it down.
I have a C# DLL file project (my_cs_dll.dll) which defines a static class with a static member function.
namespace Foo
{
public static class Bar
{
public static double GetNumber() { return 1.0; }
}
}
I also have a C++ DLL project which is using /clr.
#using <my_cs_dll.dll>
double get_number_from_cs() { return Foo::Bar::GetNumber(); }
I've added a reference to 'my_cs_dll.dll' in the C++ project Common Properties references section (copy local/copy dependencies are both True).
And I've also added the path to 'my_cs_dll.dll' in the C++ project Configuration Properties C/C++ General 'Resolve#using References' section.
Everything builds without error, however at runtime I keep getting a 'System.IO.FileNotFound' exception from the system claiming it can't find the my_cs_dll.dll assembly.
Both DLL files are definitely present in the same directory from which I'm running.
I have tried all sorts of variations on the settings mentioned above and read everything I could find on manged/unmanaged interop, but I can't seem to get my brain around what is wrong...
I'm using Visual Studio 2008 and .NET 3.5.
It sounds like your C# assembly is not being resolved at runtime. Is your C# dll in the same directory as (or a subdirectory of) your executable? It's been a while since I did this, but my recollection is that unless your assembly is installed in the GAC, it must be in the directory (or a subdirectory) where your executable is located, as opposed to the location of the dll that's using it. This has to do with the .NET security features.
If you are still having problems, you can try using resolving the assembly yourself. In your clr-enabled C++ project, try adding the following:
using namespace System;
using namespace System.Reflection;
void Resolve()
{
AppDomain::CurrentDomain->AssemblyResolve +=
gcnew ResolveEventHandler(OnAssemblyResolve);
}
Assembly ^OnAssemblyResolve(Object ^obj, ResolveEventArgs ^args)
{
#ifdef _DEBUG
String ^path = gcnew String(_T("<path to your debug directory>"));
#else
String ^path = gcnew String(_T("<path to your release directory>"));
#endif
array<String^>^ assemblies =
System::IO::Directory::GetFiles(path, _T("*.dll"));
for (long ii = 0; ii < assemblies->Length; ii++) {
AssemblyName ^name = AssemblyName::GetAssemblyName(assemblies[ii]);
if (AssemblyName::ReferenceMatchesDefinition(gcnew AssemblyName(args->Name), name)) {
return Assembly::Load(name);
}
}
return nullptr;
}
You may have to tweak the code a little bit to get it to compile in your project. In my case, I made the two functions static methods of a class in my clr-enabled project. Just make sure you call the Resolve() function early on in your code, i.e., before you try to call get_number_from_cs().
While using COM is an option, it is not necessary. You're on the right path with your current approach. If you want some hand-holding, take a look at this CodeProject example. It's the one I following to get my unmanaged application to use my managed assemblies.
F# declared namespace is not available in the c# project or visible through the object browser.
I have built a normal F# library project, but even after i build the project and reference it to my C# project, I am unable to access the desired namespace.
I am also unable to see it in the object browser, i get an error telling me that it has not been built. I am running on the september release can someone point out my error ?
F# Version 1.9.6.0
(6) Edit : Referencing the dll directly has fixed my problem, referencing the project allows me to compile but the intellisence does not work. When the dll is directly referenced the intellisence works perfectly.
This is the code found in the .fs file
#light
namespace Soilsiu.Core
module public Process =
open System.Xml.Linq
let private xname (tag:string) = XName.Get(tag)
let private tagUrl (tag:XElement) = let attribute = tag.Attribute(xname "href")
attribute.Value
let Bookmarks(xmlFile:string) =
let xml = XDocument.Load(xmlFile)
xml.Elements <| xname "A" |> Seq.map(tagUrl)
let PrintBookmarks (xmlFile:string) =
let list = Bookmarks(xmlFile)
list |> Seq.iter(fun u -> printfn "%s" u)
(5) Edit : Could ReSharper 4.0 be the problem?
(4) Edit : When i say the Object browser is unable to read the resulting assembly, i mean that when I try to open the assembly in the object browser i get an error telling me the project has not yet been built. yet again i can read the assembly using reflector.
(3) Edit : Reflector can Disassemble the dll but the Object Browser is unable to read it.
(2) Edit : I have Upgraded my F# version to 1.9.6.2 and still the same consequence
(1) Edit : I was able to Disassemble the dll to C# I get : (Everything seems to be fine here)
namespace Soilsiu.Core
{
[CompilationMapping(7)]
public static class Crawler
[CompilationMapping(7)]
public static class Process
}
[CompilationMapping(7)]
public static class Process
{
// Methods
static Process();
public static IEnumerable<string> Bookmarks(string xmlFile);
public static void PrintBookmarks(string xmlFile);
internal static string tagUrl(XElement tag);
internal static XName xname(string tag);
// Nested Types
[Serializable]
internal class clo#13 : FastFunc<XElement, string>
{
// Methods
public clo#13();
public override string Invoke(XElement tag#9);
}
[Serializable]
internal class clo#17 : FastFunc<string, Unit>
{
// Methods
public clo#17();
public override Unit Invoke(string u);
}
}
What if you reference the produced DLL directly (i.e., not via a project reference, but via a file reference)?
Maybe IntelliSense is just messed up? What compiler error do you get when you try to use it in C#? When you say "the object browser is unable to read it" what does that mean?
For what it's worth, I added this to a F# library project, referenced it (project) from a C# console app, and was able to use it. IntelliSense did not work at first though. (Had to rebuild.)
If you can make a solid repro, I'd suggest emailing it to F# bugs alias (fsbugs).
I tried the same thing. It looks as if Visual Studio and Resharper 4.0 doesn't understand F# for some reason. If you ignore the sea of red text and the lack of intellisense, it will compile fine.
Try
Make sure that C# project is targeted FULL .NET (NOT Client Profile).
Add references to assemblies into C# project which are used by F# project.