Thanks In advance for you time and Help.
Goal: I am trying to use my C# library within a C++ project
What I did:
Created a simple .dll file with my C# project. named: ClassLibrary1.dll
Created a C++ console application named: CppClr (Common Language RunTime Support Changed to: /clr)
Copied ClassLibrary1.dll to the root off CppClr project
Following is my ClassLibrary1(C#) code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ClassLibrary1
{
public class Class1
{
public static void output()
{
String mystr;
mystr = "Helloo World"; // create a new string
Console.WriteLine(mystr);
Console.WriteLine("From C++ Managed Code!");
Console.ReadLine();
}
}
}
The Following is my C++/CLI code:
#include "CppClr.h"
#using <ClassLibrary1.dll>
int main()
{
ClassLibrary1::Class1::output();
}
Problem: The error I get when I run my C++/CLI code :
An unhandled exception of type 'System.IO.FileNotFoundException' occurred in Unknown Module.Additional information: Could not load file or assembly 'ClassLibrary1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified.
Your problem is simply an issue of your C++ executable not being able find/load the C# DLL at runtime.
There are a few different places that the .NET runtime looks to load assemblies. The simplest of these is from the same directory that your compiled application is running from. It is not enough to have ClassLibrary1.dll in the root of your C++ project - it needs to be in same directory that your project is running from.
As a quick and dirty test, you should be able to verify this by copying ClassLibrary1.dll into the C++ project's output directory. If you're running in the Debug configuration, this will probably be something like C:\Projects\CppClr\Debug\ or wherever your C++ project is. Verify that this is the directory that contains the compiled CppClr.exe file. Once you copy the DLL here and run your project, the runtime should be able to find the DLL and all should be good.
However, this could be kind of a pain if you're frequently updating your C# project, since you'll continually need to copy it to the C++ output folder every time something changes. The solution to this is to add a reference in the C++ project to your C# library.
In Visual Studio, open up your C++ project. From the solution explorer, right-click on references and select Add reference... Next, click on the Browse... button at the bottom of the dialog and browse to the location of ClassLibrary1.dll on your disk. Click on Add and then OK.
Now, whenever you build the C++ project, it will copy the ClassLibrary1.dll assembly into the project's output folder. You should also be able to remove the #using <ClassLibrary1.dll> directive from the top of your C++ file, since adding the DLL as a project reference should perform the same function.
The msdn link shared by Chad is of the case when you want to add a dll created from C++ project.
What you need to do is to create a strong name for your C# library.
To create a strong name for your class library, type the following command at the Visual Studio .NET command prompt:
sn.exe -k MyKeyFile.SNK
Copy the MyKeyFile.SNK file to your project folder.
Double-click the AssemblyInfo.cs file to open the file in Solution Explorer.
Replace the following lines of code in the AssemblyInfo.cs file
[assembly: ComVisible(false)]
[assembly: AssemblyDelaySign(false)]
[assembly: AssemblyKeyFile("")]
with
[assembly: ComVisible(true)]
[assembly: AssemblyDelaySign(false)]
[assembly: AssemblyKeyFile("..\\..\\MyKeyFile.SNK")]
Press CTRL+SHIFT+B to generate the managed DLL.
Now register the managed DLL for use with COM or with Native C++
Call the Managed DLL from Native C++ Code or using it.
The link here is close to what the OP is trying to do.
https://support.microsoft.com/en-us/kb/828736
I was able to solve this problem by specifying the absolute path of the dll file.
before:
#using "ClassLibrary1.dll"
after:
#using "C:\user\ClassLibrary1\ClassLibrary1\bin\Debug\ClassLibrary1.dll"
if this works for you, you need to go to Properties -> C/C++ -> General -> "Resolve #using References" and add the path here. then you can use #using "ClassLibrary1.dll" again in your could without the complete path.
Answer was found here
Related
enter image description hereI am trying to import a dll in my c# console project.
I add the dll in the reference of the project. Right Click->add reference->browse.
The DLL is placed in my project folder as well as in program data folder in c drive.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using mcp2210;
the last line "using mcp2210;" gives an error
Error 1 The type or namespace name 'mcp2210' could not be found (are
you missing a using directive or an assembly
reference?) C:\Users\testuser\AppData\Local\Temporary
Projects\ConsoleApplication1\Program.cs
Do I need to use [DllImport("mcp2210.dll")] in my project?
How can I access the functions of this dll?
Please see the images below
edit
Hi I was able to add the dll in my project using the namespace from the object browser. However when I try to run it in debug mode I get badImageFormatException was handled popup.
Could not load file or assembly 'mcp2210_dll_m_dotnetv2_x86, Version=1.0.5980.19136, Culture=neutral, PublicKeyToken=null' or one of its dependencies. An attempt was made to load a program with an incorrect format.
Why is this happening?
Namespace has nothing to do with a DLL's name. Just because the DLL is named mcp2210 doesn't mean it contains the namespace mcp2210.
After you've added the reference, open Visual Studio's object browser. Find the DLL in the treeview on the left and expand it to discover the namespaces and classes contained in it.
Once you find it, use one of its namespaces in your using statement and you're good to go.
If you cannot browse to your DLL, it is probably the wrong type of DLL or the wrong framework version.
Make sure if it is a managed dll. If it is build using unmanaged than place this dll in bin folder manually.
just copy paste in bin
Firstly, make sure both the dll project and your separate project have the same target platform (32 bit, 64 bit, or any cpu by going to the project's properties).
Secondly, make sure you have added the dll as a reference to your project. In addition to this, place the file in your project's 'bin > debug' folder.
The path should look like this (..\Your Project\bin\Debug).
If all of that fails, double check that the Target Framework matches in each project.
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 some problems with dll. When I make dll without using of lib files (which I need), everything is fine. But when I'm trying to use some functions in dll that uses functions in lib then some exception appears:
System.DllNotFoundException, cant load a dll module (exception from HRESULT:0x8007007E).
dll file is in correct place.
P.S. using Visual Studio 2010.
What could be wrong?
More detail in the question will get you better answers. But with current information, the most likely cause is that the lib file you are referencing or one of its dependencies is unavailable. This could be because it is not in your GAC or your runtime location, a file format conflict, or a number of other things.
I'm assuming that everything compiles without errors, of course. Again, please add detail if this is not what you need.
if you are making a new class you should reference the default dlls.
in example when you make a new class library and want to use a messagebox in your code ,
you should first reference that required dll in your program(i dont mean your dll,i mean dot net default dll like system.windows.forms) and then add using something; in the top of your class.
example : we want use messagebox in a class library then :
1. first from solution explorer right click the project > add reference ,now reference manager opens now from left tabs click assemblies then framework and then find and select system.windows.forms
2. now its time to use it in our program first add this line in very top of your class file
using System.Windows.Forms; //add this line in top of your class
after that we can use messagebox without any compiler errors.
keep in mind any other dll files should be referenced this way but in windows form applications default lib files are referenced by default
I need to implement a wrapper to expose some native C++ code to C#, and have followed this tutorial:
http://www.silverlightshow.net/items/Windows-Phone-8-Native-Code-Support.aspx
So far in my C# test project, I don't have problems instantiating a class written in C++/CX from the Runtime Component project and using methods from that class, so long as I reference the entire project (.sln).
Visual Studio doesn't allow me to reference the Runtime Component DLL alone, but does allow me to reference the .winmd file in the project. C# then recognizes the namespace correctly, however at runtime I get a TypeLoadException when trying to create the same object.
This doesn't appear to be a namespace problem (as mentioned here: Changing namespace name of C++ component in Windows Phone causes exception), since everything is alright so long as I create a project reference (or does referencing a project vs a .winmd affect the namespace somehow?).
Is it possible to bundle the Runtime Component in some form that an end user can reference it without needing to provide the entire project?
You need to add following the to WMAppManifest.xml
<ActivatableClasses>
<InProcessServer>
<Path>YourComponent.dll</Path>
<ActivatableClass ThreadingModel="both" ActivatableClassId="YourComponentNamespace.YourComponent"/>
</InProcessServer>
</ActivatableClasses>
With YourComponent being the name of your WinMD.
I think what you are seeing is a manifestation of the problem described here.
In short, when creating a WinRT component using C++, just referencing the output DLL or the output winmd is not sufficient. You need both.
I had this same problem, and (eventually) figured out that the .dll and .winmd file needed to have the same name (which was the same as the namespace they defined) and be in the same directory.
For example, if your classes are in the X::Y namespace, the files must be X.Y.dll and X.Y.winmd.
Then all I needed to do was add a reference to the .winmd file in my project (by right-clicking on the References folder for that project in the Solution Explorer, choosing "Add Reference...", then choosing "Browse" from the dialog that comes up). I didn't need to add anything to the manifest file.
In my project I have an unmanaged native C++ dll and a C# application. I am trying to import a function from the unmanaged dll using DllImport but I keep getting a DllNotFoundException.
Here is my code that calls the DLL.
using System.Runtime.InteropServices;
namespace TestApp
{
public delegate void UpdateDelegate(string s);
class Program
{
[DllImport("CGPUnmanagedLibrary.dll")]
internal static extern int parse_raw_gsod_file(
[MarshalAs(UnmanagedType.LPStr)]
string filePath,
int minTemp,
UpdateDelegate callBack);
static void Main(string[] args)
{
UpdateDelegate myCallBack = new UpdateDelegate(Program.Report);
string path = #"C:\Creative Solutions\Projects\Clyde's Garden Planner\Frost Data Database\GSOD Data\GSOD_RAW_DATA\1992\gsod_1992.txt";
int result = parse_raw_gsod_file(path, 32, myCallBack);
Console.Write("Parse completed with exit code: " + result.ToString());
Console.ReadLine();
} // end main function
public static void Report(string msg)
{
Console.Write("Message is ");
Console.WriteLine(msg);
}
} // End class
} // end namespace
I tried copying the DLL to the app output directory but it still can't find it. I also tried adding the DLL project as a reference but I get a popup window saying it can't be added. How do you properly link an unmanged DLL to a managed application?
Update - Here is the full error:
Unable to load DLL 'CGPUnmanagedLibrary': The specified module could not be found. (Exception from HRESULT: 0x8007007E)
Update 2 - I know for sure that the DLL is in the same directory as the .exe trying to load it. This makes me think there is a dependency in the DLL that isn't getting loaded. I'm only using basic C++ libraries in the DLL (string, math, iostream, etc). Any ideas what could not be loading and why?
Update 3 - Tested with Dependency Walker
Loading my unmanaged C++ DLL in dependency walker showed no errors. I also tried to open my executable in dependency walker and it showed errors loading two DLLs: GPSVC.DLL and IESHIMS.DLL - doesn't make any sense because I am only using standard c++ libraries in my code. I think it may have something to do with the fact that I have a managed C++/CLI DLL trying to load the unmanaged DLL as well (I was trying to implement some C++/CLI wrappers). Anyway, I have since started a new VS solution and moved on. See my answer.
In all likelihood the problem isn't the DLL you're trying to load but one of its (chained) dependencies. Run depends.exe or a similar utility on the DLL to see if all the dependencies can be found. The misleading message "The specified module could not be found" has become a classic annoyance (if not FAQ material!): it leads you to think that your DLL is not being found when almost all of the time it's one of its dependencies that's not being found.
To test, the *.dll needs to be in the same directory as the .exe that is trying to load it. Don't trust Visual Studio to do it for you at this point. Physically copy the file to C:******\Debug\x86\bin\ or whichever configuration you are running under. If in doubt, copy it to all of your bin folders. After you figure out the path, then you start finding ways to automate the project build to copy the file correctly. If that doesn't do it, put it in system32--it will certainly find it there. However, if after doing these things, you still can't find it. There is probably a dependency to your unmanaged dll that is also missing.
First I want to thank everyone for their help. Unfortunately I never did solve this issue (see edits in my main question). The answer turned out to be starting a totally new Visual Studio solution and creating two new projects: C# app and C++ dll. I did away with the need for wrappers as I am now just marshaling two main functions.
Thanks again.
The anwer of user arayq2 made much sense and I was quickly able to solve my problem also.
The dll that couldn't be loaded (DllNotFoundException) in my case is depending upon another dll. This dll (that is not part of my project) was actually compiled with newer versions of certain .h and .lib files. Older versions of these .h and .lib files (with the same filename) were part of the project that compiled the dll that couldn't be loaded.
After I updated my dll project with the newer versions of these .h and .lib files and recompiling my dll project, my problem was solved.
Thank you arayq2!