reference a C++ dll in a C# program

[robert201]

Hello,

VS 3.5

I have created a simple C++ DLL, and I want to use this in my C# program.

However, I am getting a Can't find PInvoke DLL 'TEST_SIP.dll

I have placed the DLL in my debug folder where my C# program is executed from. I am not sure if that is the correct place to put it.

Not sure where I am going wrong with this one.

many thanks for any suggestions,

Steve

Code in my C#

[DllImport("TEST_SIP.dll")]
        public static extern double Add(double a, double b);

         private void btnLogin_Click_1(object sender, EventArgs e)
        {
            string msg = SendData("Hello how are you");//Can't find PInvoke DLL 'TEST_SIP.dll'.
            MessageBox.Show(msg);
        }

C++ header

//TEST_SIP.h
#include <iostream>

namespace TEST_SIP
{
	class TEST_SIP_Phone
	{
	public:
		static _declspec(dllexport) double Add(double a, double b);
		static _declspec(dllexport) double Subtract(double a, double b);
		static _declspec(dllexport) double Multiply(double a, double b);
		static _declspec(dllexport) double Divide(double a, double b);
		static _declspec(dllexport) std::string SendData(std::string data);
	};
}

C++ Functions

//TEST_SIP.cpp
#include "TEST_SIP.h"
#include <stdexcept>
#include <cctype>

using namespace std;

namespace TEST_SIP
{
	double TEST_SIP_Phone::Add(double a, double b)
	{
		return a + b;
	}
	double TEST_SIP_Phone::Subtract(double a, double b)
	{
		return a - b;
	}
	double TEST_SIP_Phone::Multiply(double a, double b)
	{
		return a * b;
	}
	double TEST_SIP_Phone::Divide(double a, double b)
	{
		if(b == 0)
		{
			throw new invalid_argument("b cannot be zero!");
		}

		return a / b;
	}
	std::string TEST_SIP_Phone::SendData(std::string data)
	{
		return data;		
	}	
}

 

[AlexCuse]

Did you add a reference?

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[robert201]

Hello,

I was thinking about that. However, the documents I read said nothing about adding a reference.

How would I add a reference?

Many thank for your help,

Steve

 

[AlexCuse]

Go to Project --> Add Reference.

Then click the "Browse" tab and browse to your DLL's location, and add the reference.

Hope this helps,

Alex

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[robert201]

Hello,

I went to browse for the dll, however when I click ok to add it I get the following message: "A reference to 'TEST_SIP' could not be added"

Thanks for anymore advice,

Steve

 

[JurkMonkey]

Register your dll using regsvr32 on the command line

http://www.ubuntu.com/

 

[robert201]

Hello,

I found the solution.

You have to create a SmartDevice WIN32 DLL. Add it into your project. Project | Existing Item | Set it property to "copy if newer".

The code is pretty much the same.

Steve

 

[AlexCuse]

FWIW, you probably ought to mention you're using the compact framework sooner in the future...

Glad you got it working

Alex

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