Update
I have now run through the tutorial 3 times with the same results (Visual Studio/Windows is unable to recognise the DLL as a valid file). This must be an issue with my environment, as mike below ran through the tutorial and it worked fine.
I did notice this in the C++ project's solution explorer on my last run:
Does anyone know if this is okay? There seems to be a lot of Red stop-signs which to me would suggest something bad...
Following this tutorial, I have ended up with the following:
C#
using System.Runtime.InteropServices;
namespace TestImport
{
class Program
{
[DllImport("TestLib.dll")]
public static extern void DisplayHelloFromDLL();
static void Main(string[] args)
{
DisplayHelloFromDLL();
}
}
}
C++
In .cpp file Source Files
#include <stdio.h>
extern "C"
{
__declspec(dllexport) void DisplayHelloFromDLL()
{
printf("Hello from DLL !\n");
}
}
When debugging in Visual Studio:
An unhandled exception of type 'System.DllNotFoundException' occurred in TestImport.exe
Additional information: An attempt was made to load a program with an incorrect format. (Exception from HRESULT: 0x8007000B)
When running the built EXE (from he same folder as the Dll):
An attempt was made to load a program with an incorrect format.
Have I done anything wrong in the above code?
I did do all of this in VS 2015, where the tutorial calls for VS 2010, howeve rI couldn't find a more up-to-date tutorial.
When I try to add the project as a reference by Project -> Add Reference ... I am seeing this error:
A reference to 'Path\To\MyLib.dll' could not be added. Please make sure
that the file is accessible, and that it is a valid assembly or COM
component.
Which makes me think that the issue is either with the source code or the DLLs configuration.
I have also tried building both files and putting them in the same folder before running the Executable, but without any improved results (same error as when running the EXE above).
Solution Explorer Screenshot:
Make sure the name of your C++ project and DllImport parameter are the same. Also, if the dll file is not located in the same directory as your C# project, make sure to add the dll into your Debug/Release folder.
Also! Make sure that you are running in the same 32/64 bit mode when compiling.. if you compiled the dll using 32 bit and try to use it in a 64 bit C# program, it won't work.
OK, now build this application, and then copy the previously built DLL into the Debug/Release directory of the current application. The DLL should be in the same directory as your main application.
Did you do the bolded text? Your C# app won't know where to look for the DLL and it looks in the build folder, by default.
An unhandled exception of type 'System.DllNotFoundException'
It happened to me, because of the imported c++ dll, its own dependency dlls were missing.
After copying them into Debug/Release folder everything worked.
I have a program written in C#. I want to use a DLL made in C within this program.
public class Test
{
[DllImport(#"C:/.../surcouche2.dll")]
public static extern int refreshEntities();
}
I call the function as:
Test.refreshEntities();
I am using Visual Studio. To create the DLL surcouche2.dll, I created a new Visual C++ Application Console, then I chose DLL and left the options on their defaults. Then, I told to VS to compile using C.
The function is :
__declspec(dllexport) int refreshEntities() {
int ret = 0;
LibData *n;
n = newLibData(LIB_MODULES_MODULE_ENTITES, LIB_MODULES_ACTION_SELECT,
"http://10.0.2.2:4242/WebService1.asmx");
if (n)
{
ret = n->refreshDb(n);
n->destroy(n);
}
return (ret);
}
The functions called in are in another DLL (that is referenced). But I get this error:
system.DllNotFoundException: Impossible de charger la DLL 'C:/.../surcouche2.dll': Le module spécifié est introuvable. (Exception de HRESULT : 0x8007007E)
à app.Lol.refreshEntities()
à app.MainWindow..ctor() dans c:\...\MainWindow.xaml.cs:ligne 30
But, if I change the function refreshEntities like this, then it works fine:
__declspec(dllexport) int refreshEntities() {
return (42);
}
The second DLL uses another DLL (both in C). I created them with the option "create an empty project" so I haven't the stdafx.h, ... files. I guess it's not a problem because I can use a function from the third DLL in the second one.
This error can happen if a dependency of loaded dll can't be resolved.
First of all I propose you to put both native assemblies in a bin folder and change a reference
from [DllImport(#"C:/.../surcouche2.dll")] to [DllImport("surcouche2.dll")]
In general to debug dependency issues tools like Dependency Walker and Process Monitor can be useful. First helps to understand what the dependencies are, second to check there your application is trying to find the assemplies.
Configure Process Monitor's to show process activity only and apply process name filter with your application name like on the picture below and you will get all files your app trying to access. It will help to find missing dll's.
[DllImport(#"C:/.../surcouche2.dll")]
This is bad idea, you are getting a preview of what is going to go wrong on your user's machine as well. Hard-coding the path to the DLL like that helps the pinvoke marshaller to find the DLL file on disk. But it does absolutely nothing to help the operating system to find DLLs that surchouce2.dll needs. Like the one that contains the newLibData() function.
The error message is often mis-interpreted. It says it "cannot load" surcouche2.dll. Which is accurate, but most programmers will read the message as "cannot find" surcouche2.dll. The most common reason for the exception. Not the problem here.
Never mess with DLL Hell. The days that keeping DLLs in a separate directory and sharing them between different programs was useful are long, long gone. Always copy dependent DLLs into the same directory as the EXE that needs them. Makes it very easy on the operating system to find them. And avoids the considerable misery you'll have to deal with when it finds the wrong file.
Use Project + Add Existing Item and select the DLLs. Set their Copy Local property to True. If you don't like the clutter then use XCOPY in a post-build event.
I am developing an application that communicates with some hardware using the C++ DLL provided by the hardware provider. I also have a header file for this DLL, but no source file. In my C# application, I'm trying to import and call the DLL's functions like this:
public class MyClass
{
[DllImport("CaGe.dll")]
public static extern long someLibraryFunction();
public void callLibFunction()
{
Console.WriteLine("function call: " + someLibraryFunction());
}
}
The library.dll file is located in the same folder as the MyClass.cs file and also the rest of the project files. When I start the debugging session however, I first receive a dialog window from system saying: CAGE InitDll: Erro on load library "CdbClientInit" and after I click OK on that, an unhalted exception on the line where I call the library function occours.
The exception says: System.DllNotFoundException: Exception from HRESULT: 0x8007045A
I found on the internet that this may be caused by a missing DLL that the CaGe.dll needs, so I tried to put the DLL through the Dependency Walker, but the results are a little bit confusing for me. Under the CAGE.DLL there are WS32_32.DLL, VERSION.DLL, KERNEL.DLL and USER32.DLL tabs, I susspect that the libraries I need are somwhere under the USER32.DLL tab, but I don't recognize any of them (if a missing DLL is what is causing this problem).
Any advice would be much appretiated :)
More help to use C++ function in C# please check below URL
http://www.codeproject.com/Questions/107152/Using-a-C-dll-in-a-C-application
I have several Unmanaged C++ written lib files which I need to link to Managed C++ dll.
Then I need to invoke functions of this Managed C++ from C# application.
First step is OK - Managed C++ dll is created, I can see with ildasm that it exports functions I need. However when I try to call this function from my C#-written test app it says:
An unhandled exception of type 'System.IO.FileLoadException' occurred in Unknown Module.
A procedure imported by {MyManagedCPP.dll} could not be loaded.
This message goes from VS2010.
I made simple experiment - removed dependencies from all lib files in Managed C++ dll and rebuild it.
With this change it is OK - app starts, I can call functions of Managed C++ dll from C# test app.
Is it not possible by design to call managed c++ functions when dll has static linkage with lib files? Technical restriction? Or there is some workaround?
Thanks
You no doubt have an implicit dependency on a native DLL. It isn't clear from the question what DLL that might be. It could be msvcrxx.dll for example, a runtime support library for native C++ code. Which would be rather bad, you don't want to mix CRT versions. Such a missing DLL otherwise prevents the C++/CLI assembly from getting loaded, producing the FileLoadException.
If you have no idea what that DLL might be then you could use SysInternals' ProcMon utility. The trace will show you the program searching for the DLL and not finding it. If it is msvcrxx.dll then be sure to rebuild the .lib files using the same compiler version you used to build the C++/CLI assembly. If it is something else then make sure you copy that DLL to the build directory.
I have a Windows C# program that uses a C++ dll for data i/o. My goal is to deploy the application as a single EXE.
What are the steps to create such an executable?
Single Assembly Deployment of Managed and Unmanaged Code
Sunday, February 4, 2007
.NET developers love XCOPY deployment. And they love single assembly components. At least I always feel kinda uneasy, if I have to use some component and need remember a list of files to also include with the main assembly of that component. So when I recently had to develop a managed code component and had to augment it with some unmanaged code from a C DLL (thx to Marcus Heege for helping me with this!), I thought about how to make it easier to deploy the two DLLs. If this were just two assemblies I could have used ILmerge to pack them up in just one file. But this doesn´t work for mixed code components with managed as well as unmanaged DLLs.
So here´s what I came up with for a solution:
I include whatever DLLs I want to deploy with my component´s main assembly as embedded resources.
Then I set up a class constructor to extract those DLLs like below. The class ctor is called just once within each AppDomain so it´s a neglible overhead, I think.
namespace MyLib
{
public class MyClass
{
static MyClass()
{
ResourceExtractor.ExtractResourceToFile("MyLib.ManagedService.dll", "managedservice.dll");
ResourceExtractor.ExtractResourceToFile("MyLib.UnmanagedService.dll", "unmanagedservice.dll");
}
...
In this example I included two DLLs as resources, one being an unmanaged code DLL, and one being a managed code DLL (just for demonstration purposes), to show, how this technique works for both kinds of code.
The code to extract the DLLs into files of their own is simple:
public static class ResourceExtractor
{
public static void ExtractResourceToFile(string resourceName, string filename)
{
if (!System.IO.File.Exists(filename))
using (System.IO.Stream s = System.Reflection.Assembly.GetExecutingAssembly().GetManifestResourceStream(resourceName))
using (System.IO.FileStream fs = new System.IO.FileStream(filename, System.IO.FileMode.Create))
{
byte[] b = new byte[s.Length];
s.Read(b, 0, b.Length);
fs.Write(b, 0, b.Length);
}
}
}
Working with a managed code assembly like this is the same as usual - almost. You reference it (here: ManagedService.dll) in your component´s main project (here: MyLib), but set the Copy Local property to false. Additionally you link in the assembly as an Existing Item and set the Build Action to Embedded Resource.
For the unmanaged code (here: UnmanagedService.dll) you just link in the DLL as an Existing Item and set the Build Action to Embedded Resource. To access its functions use the DllImport attribute as usual, e.g.
[DllImport("unmanagedservice.dll")] public extern static int Add(int a, int b);
That´s it! As soon as you create the first instance of the class with the static ctor the embedded DLLs get extracted into files of their own and are ready to use as if you deployed them as separate files. As long as you have write permissions for the execution directory this should work fine for you. At least for prototypical code I think this way of single assembly deployment is quite convenient.
Enjoy!
http://weblogs.asp.net/ralfw/archive/2007/02/04/single-assembly-deployment-of-managed-and-unmanaged-code.aspx
Try boxedapp; it allows to load all DLLs from memory. Also, it seems that you can even embed .net runtime. Good to create a really standalone applications...
Use Fody.Costura nuget
Open your solution -> Project -> Manage Nuget Packages
Search for Fody.Costura
Compile your project.
That's it !
Source:
http://www.manuelmeyer.net/2016/01/net-power-tip-10-merging-assemblies/
Have you tried ILMerge? http://research.microsoft.com/~mbarnett/ILMerge.aspx
ILMerge is a utility that can be used to merge multiple .NET assemblies into a single assembly. It is freely available for use from the Tools & Utilities page at the Microsoft .NET Framework Developer Center.
If you're building the C++ DLL with the /clr flag (all or partially C++/CLI), then it should work:
ilmerge /out:Composite.exe MyMainApp.exe Utility.dll
It will not work with an ordinary (native) Windows DLL however.
Just right-click your project in Visual Studio, choose Project Properties -> Resources -> Add Resource -> Add Existing File…
And include the code below to your App.xaml.cs or equivalent.
public App()
{
AppDomain.CurrentDomain.AssemblyResolve +=new ResolveEventHandler(CurrentDomain_AssemblyResolve);
}
System.Reflection.Assembly CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs args)
{
string dllName = args.Name.Contains(',') ? args.Name.Substring(0, args.Name.IndexOf(',')) : args.Name.Replace(".dll","");
dllName = dllName.Replace(".", "_");
if (dllName.EndsWith("_resources")) return null;
System.Resources.ResourceManager rm = new System.Resources.ResourceManager(GetType().Namespace + ".Properties.Resources", System.Reflection.Assembly.GetExecutingAssembly());
byte[] bytes = (byte[])rm.GetObject(dllName);
return System.Reflection.Assembly.Load(bytes);
}
Here's my original blog post:
http://codeblog.larsholm.net/2011/06/embed-dlls-easily-in-a-net-assembly/
Thinstall is one solution. For a native windows application I would suggest embedding the DLL as a binary resource object, then extracting it at runtime before you need it.
Smart Assembly can do this and more. If your dll has unmanaged code, it wont let you merge the dlls to a single assembly, instead it can embed the required dependencies as resources to your main exe. Its flip-side, its not free.
You can do this manually by embedding dll to your resources and then relying on AppDomain's Assembly ResolveHandler. When it comes to mixed mode dlls, I found many of the variants and flavours of ResolveHandler approach to not work for me (all which read dll bytes to memory and read from it). They all worked for managed dlls. Here is what worked for me:
static void Main()
{
AppDomain.CurrentDomain.AssemblyResolve += (sender, args) =>
{
string assemblyName = new AssemblyName(args.Name).Name;
if (assemblyName.EndsWith(".resources"))
return null;
string dllName = assemblyName + ".dll";
string dllFullPath = Path.Combine(GetMyApplicationSpecificPath(), dllName);
using (Stream s = Assembly.GetEntryAssembly().GetManifestResourceStream(typeof(Program).Namespace + ".Resources." + dllName))
{
byte[] data = new byte[stream.Length];
s.Read(data, 0, data.Length);
//or just byte[] data = new BinaryReader(s).ReadBytes((int)s.Length);
File.WriteAllBytes(dllFullPath, data);
}
return Assembly.LoadFrom(dllFullPath);
};
}
The key here is to write the bytes to a file and load from its location. To avoid chicken and egg problem, you have to ensure you declare the handler before accessing assembly and that you do not access the assembly members (or instantiate anything that has to deal with the assembly) inside the loading (assembly resolving) part. Also take care to ensure GetMyApplicationSpecificPath() is not any temp directory since temp files could be attempted to get erased by other programs or by yourself (not that it will get deleted while your program is accessing the dll, but at least its a nuisance. AppData is good location). Also note that you have to write the bytes each time, you cant load from location just 'cos the dll already resides there.
If the assembly is fully unmanaged, you can see this link or this as to how to load such dlls.
If you want to pack an application that already exists (including its dlls and other resources, no matter what language it's coded in) into a single .exe you can use SerGreen's Appacker for that purpose. But it'll be "detected" to "run malicious code from a hacker" because it unpacks itself:
Appacker and packages created by it can be detected as malware by some antivirus software. That's because of a hacky way i used to package files: packed app reads its own executable and extracts other files from it, which antiviruses find hella suspicious. It's false positive, but it still gets in the way of using this app.
-SerGreen on GitHub
To use it you can simply open it up, click away any virus warnings (and tell Windows Defender to not delete it!), then choose a directory that should be packed and the executable to be run after unpacking.
You can optionally change the unpacking behaviour of the app (windowed/windowless unpacker, unpacking target directory, should it be repacked or changes to the unpacked files be ignored, ...)
PostBuild from Xenocode can package up both managed and unmanged into a single exe.