Qt程序中调用C#编写的dll(推荐)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace CSharpDll
{
 public class CSharpClass
 {
 public CSharpClass() { }
 public int add(int a , int b)
 {
 return a + b;
 }

 public void substract( int a , int b , ref int c)
 {
 c = a - b;
 }

 public static void showBox(string str)
 {
 MessageBox.Show("C#:" + str);
 }
 }
}

// CppDll.h

#pragma once

using namespace System;
using namespace System::Reflection;

__declspec(dllexport) int add(int a, int b)
{
	CSharpDll::CSharpClass obj;
	return obj.add(a, b);
}

__declspec(dllexport) void substract(int a, int b, int *c)
{
	CSharpDll::CSharpClass obj;
	obj.substract(a, b, *c);
}

__declspec(dllexport) void showBox(const char* content)
{
	CSharpDll::CSharpClass obj;
	String^ str = gcnew String(content);
	obj.showBox(str);
}

namespace CppDll {

	public ref class Class1
	{
		// TODO: 在此处添加此类的方法。
	};
}

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include<QLibrary>
#include<QMessageBox>
typedef int (*x_add)(int a , int b);
typedef void (*x_substract)(int a , int b , int* c);
typedef void (*x_showBox)(const char* content);

MainWindow::MainWindow(QWidget *parent) :
 QMainWindow(parent),
 ui(new Ui::MainWindow)
{
 ui->setupUi(this);
}

MainWindow::~MainWindow()
{
 delete ui;
}

//add
void MainWindow::on_pushButton_clicked()
{
 int a = ui->lineEdit->text().toInt();
 int b = ui->lineEdit_2->text().toInt();
 QLibrary library("./CppDll.dll");
 if(library.load()){
 x_add add = (x_add)library.resolve("?add@@YAHHH@Z");
 if(add){
 QString str = QString::number(add(a , b));
 QMessageBox::information(this , "call add from dll" , str);
 }
 }
}

//sub
void MainWindow::on_pushButton_2_clicked()
{
 int a = ui->lineEdit_3->text().toInt();
 int b = ui->lineEdit_4->text().toInt();
 int c = 0;
 QLibrary library("./CppDll.dll");
 if(library.load()){
 x_substract sub = (x_substract)library.resolve("?substract@@YAXHHPAH@Z");
 if(sub){
 sub(a , b , &c);
 QString str = QString::number(c);
 QMessageBox::information(this , "call sub from dll" , str);
 }
 }
}

//showBox
void MainWindow::on_pushButton_3_clicked()
{
 QLibrary library("./CppDll.dll");
 if(library.load()){
 x_showBox showBox = (x_showBox)library.resolve("?showBox@@YAXPBD@Z");
 if(showBox){
 showBox("showBox!");
 }
 }
}