C# 通过dllImport 调用C++ Dll 小总结

时间：2011-04-08 来源：xiaokang088

C# 调用C++的dll，通过DllImport方式。

以下例子包含以下几种参数传递方式：

传递string、Int、Int数组、结构体、结构体数组。

比较懒，没写注释，呵呵，各位辛苦了。

demo在这里

C++ Dll 如下：

// dllmain.cpp : Defines the entry point for the DLL application.
#include "stdafx.h"
#include <stdio.h>
#include <tchar.h>

BOOL APIENTRY DllMain( HMODULE hModule,
                       DWORD  ul_reason_for_call,
                       LPVOID lpReserved
                                         )
{
        switch (ul_reason_for_call)
        {
        case DLL_PROCESS_ATTACH:
        case DLL_THREAD_ATTACH:
        case DLL_THREAD_DETACH:
        case DLL_PROCESS_DETACH:
                break;
        }
        return TRUE;
}

struct PersonInfo
{
        int id;
        wchar_t name;
};


struct StudentInfo
{
        int id;
        wchar_t name[100];
};


int Add(int para1,int para2)
{
        return para1+para2;
};

int TestStruct(struct PersonInfo* person)
{
        person->id=10;
        return 0;
};

int TestStructArray(struct  PersonInfo   persons[5] )
{
        persons[0].id=11;
        persons[0].name = L'a';

        persons[1].id=22;
        persons[1].name = L'b';

        persons[2].id=33;
        persons[2].name = L'c';

        persons[3].id=44;
        persons[3].name = L'd';

        persons[4].id=55;
        persons[4].name = L'e';

        return 0;
};

int TestStructArray2(struct  StudentInfo   students[3] )
{
        students[0].id=11;
        wcscpy(students[0].name,L"aaaaaaa");
        
        TCHAR szMsg[200] = {0};
        _stprintf_s(szMsg, 200, _T("size of PersonInfo2:%d"), sizeof(StudentInfo));
        ::OutputDebugString(szMsg);

        students[1].id=22;
        wcscpy(students[1].name,L"bbbb");

        students[2].id=33;
        wcscpy(students[2].name,L"ccc");

        return 0;
};




int TestIntArr(int tt[5])
{
        tt[0]=0;
        tt[1]=1;
        tt[2]=2;
        tt[3]=3;
        tt[4]=4;

        return 0;
}

int TestString(LPTSTR buffer, DWORD size)
{
        wcscpy_s(buffer,size,L"eststsetwet");
        return 0;
}

C++ def文件如下：

LIBRARY    "Win32Dll"

EXPORTS
         Add
         TestStruct
         TestStructArray
         TestStructArray2
         TestIntArr
         TestString

C# 调用代码如下：

    /// <summary>
    /// Interaction logic for Window1.xaml
    /// </summary>
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
            Loaded += new RoutedEventHandler(button1_Click);
        }

        private void button1_Click(object sender, RoutedEventArgs e)
        {
            int num1 = 0, num2 = 0;
            if (!string.IsNullOrEmpty(textBox1.Text) && !string.IsNullOrEmpty(textBox2.Text))
            {
                num1 = Convert.ToInt32(textBox1.Text);
                num2 = Convert.ToInt32(textBox2.Text);

                int ret = DllTest.Add(Convert.ToInt32(textBox1.Text), Convert.ToInt32(textBox2.Text));
                textBlock3.Text = ret.ToString();
            }

            PersonInfo p = new PersonInfo();
            DllTest.TestStruct(ref p);

            //int dd = p.id;

            int[] intArray = new int[5];
            DllTest.TestIntArr(intArray);
            Debug.WriteLine(intArray);

            PersonInfo[] ps = new PersonInfo[5];
            DllTest.TestStructArray(ps);

            int t = Marshal.SizeOf(new StudentInfo());
            //  var t = sizeof(PersonInfo2);

            StudentInfo[] ps2 = new StudentInfo[3];
            DllTest.TestStructArray2(ps2);

            short[] name = ps2[0].name;
            string ret13 = new string(name.Where(o => o != 0).Select(o => (char)o).ToArray());

            char[] chars = new char[100];

            StringBuilder builder = new StringBuilder(256);
            DllTest.TestString(builder, 256);
        }

    }


    public class DllTest
    {
        [DllImport("Win32Dll.dll", EntryPoint = "Add")]
        public static extern Int32 Add(int a, int b);

        [DllImport("Win32Dll.dll", EntryPoint = "TestStruct")]
        public static extern Int32 TestStruct(ref PersonInfo person);

        [DllImport("Win32Dll.dll", EntryPoint = "TestStructArray")]
        public static extern Int32 TestStructArray([In, Out]  PersonInfo[] persons);

        [DllImport("Win32Dll.dll", EntryPoint = "TestStructArray2")]
        public static extern Int32 TestStructArray2([In, Out]  StudentInfo[] students);

        [DllImport("Win32Dll.dll", EntryPoint = "TestIntArr")]
        public static extern Int32 TestIntArr([In, Out] int[] intArray);

        [DllImport("Win32Dll.dll", EntryPoint = "TestString")]
        public static extern Int32 TestString([MarshalAs(UnmanagedType.LPTStr)]StringBuilder buffer, Int32 length);
    }

    [ComVisible(false), StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
    public struct PersonInfo
    {
        public int id;
        public char name;
    }

    [StructLayout(LayoutKind.Sequential)]
    public struct StudentInfo
    {
        public int id;

        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 100)]
        public short[] name;
    }