Use library in windows form application - c++-cli

Question

I need to use WinSparkle library in my Windows Form Application. I have include library header - <winsparkle.h> and have placed DLL import code. I suppose Dll import code is C# style. How to convert it to C++ .Net style?
// AutoUpdate.cpp : main project file.
#include "stdafx.h"
#include "Form1.h"
#include <winsparkle.h>
using System;
using System::Runtime::InteropServices;
using namespace AutoUpdate;
namespace AutoUpdate // YOUR NAMESPACE CAN GO HERE
{
**// C# lines**
class WinSparkle
{
// Note that some of these functions are not implemented by WinSparkle YET.
[DllImport("WinSparkle.dll", CallingConvention=CallingConvention.Cdecl)]
public static extern void win_sparkle_init();
[DllImport("WinSparkle.dll", CallingConvention=CallingConvention.Cdecl)]
public static extern void win_sparkle_cleanup();
[DllImport("WinSparkle.dll", CharSet=CharSet.Ansi, CallingConvention=CallingConvention.Cdecl)]
public static extern void win_sparkle_set_appcast_url(String url);
[DllImport("WinSparkle.dll", CharSet=CharSet.Unicode, CallingConvention=CallingConvention.Cdecl)]
public static extern void win_sparkle_set_app_details(String company_name,
String app_name,
String app_version);
[DllImport("WinSparkle.dll", CharSet=CharSet.Ansi, CallingConvention=CallingConvention.Cdecl)]
public static extern void win_sparkle_set_registry_path(String path);
[DllImport("WinSparkle.dll", CallingConvention=CallingConvention.Cdecl)]
public static extern void win_sparkle_check_update_with_ui();
}
}
[STAThreadAttribute]
int main(array<System::String ^> ^args)
{
// Enabling Windows XP visual effects before any controls are created
Application::EnableVisualStyles();
Application::SetCompatibleTextRenderingDefault(false);
// Create the main window and run it
Application::Run(gcnew Form1());
return 0;
}

Answer 1

You seem to be getting a little confused here.
You certainly could do this with a mixed mode C++/CLI assembly. You'd include the header file and pass the lib file to the linker. Then you could call the functions directly since they are declared in the header file. You'd need to call the functions from the C++/CLI assembly, or expose whatever is needed through a managed ref class for consumption by the C# code.
However, the document you link to does not suggest this route. It suggests no C++/CLI at all and a pure C# p/invoke solution. That would appear to be the simplest approach.
I recommend that you remove the C++/CLI layer and instead use pure C# p/invoke. Follow precisely the instructions to which you linked. Start from the section titled Managed code / .NET / C# applications.