[推荐] C#调用dll(C++(Win32))时的类型转换总结

分类:.Net知识问答| 发布:camnprbubuol| 查看: | 发表时间:2011/3/25

 


C++(Win 32)

C#

char**

作为输入参数转为char[]通过Encoding类对这个string[]进行编码后得到的一个char[]

作为输出参数转为byte[]通过Encoding类对这个byte[]进行解码,得到字符串

C++ Dll接口:

void CplusplusToCsharp(in char** AgentID, out char** AgentIP);

C#中的声明:

[DllImport("Example.dll")]

public static extern void CplusplusToCsharp(char[] AgentID, byte[] AgentIP);

C#中的调用:

Encoding encode = Encoding.Default;

byte[] tAgentID;

byte[] tAgentIP;

string[] AgentIP;

tAgentID = new byte[100];

tAgentIP = new byte[100];

CplusplusToCsharp(encode.GetChars(tAgentID), tAgentIP);

AgentIP[i] = encode.GetString(tAgentIP,i*Length,Length);

Handle

IntPtr

Hwnd

IntPtr

int*

ref int

int&

ref int

void*

IntPtr

unsigned char*

ref byte

BOOL

bool

DWORD

int  uintint 更常用一些)

枚举类型

Win32

BOOL MessageBeep(UINT uType // 声音类型); 其中的声音类型为枚举类型中的某一值。

C#

用户需要自己定义一个枚举类型:

public enum BeepType

{

  SimpleBeep = -1,

  IconAsterisk = 0x00000040,

  IconExclamation = 0x00000030,

  IconHand = 0x00000010,

  IconQuestion = 0x00000020,

  Ok = 0x00000000,

}

C#中导入该函数:

[DllImport("user32.dll")]

public static extern bool MessageBeep(BeepType beepType);

C#中调用该函数:

MessageBeep(BeepType.IconQuestion);

结构类型

Win32

使用结构指针作为参数的函数:

BOOL GetSystemPowerStatus(

 LPSYSTEM_POWER_STATUS lpSystemPowerStatus

);

Win32中该结构体的定义:

typedef struct _SYSTEM_POWER_STATUS {

BYTE  ACLineStatus;

BYTE  BatteryFlag;

BYTE  BatteryLifePercent;

BYTE  Reserved1;

DWORD BatteryLifeTime;

DWORD BatteryFullLifeTime;

} SYSTEM_POWER_STATUS, *LPSYSTEM_POWER_STATUS;

C#

用户自定义相应的结构体:

struct SystemPowerStatus

{

  byte ACLineStatus;

  byte batteryFlag;

  byte batteryLifePercent;

  byte reserved1;

  int batteryLifeTime;

  int batteryFullLifeTime;

}

C#中导入该函数:

[DllImport("kernel32.dll")]

public static extern bool GetSystemPowerStatus(

  ref SystemPowerStatus systemPowerStatus);

C#中调用该函数:

SystemPowerStatus sps;

….sps初始化赋值……

GetSystemPowerStatus(ref sps);

字符串

对于字符串的处理分为以下几种情况:

1、  字符串常量指针的处理(LPCTSTR),也适应于字符串常量的处理,.net中的string类型是不可变的类型。

2、  字符串缓冲区的处理(char*),即对于变长字符串的处理,.netStringBuilder可用作缓冲区

Win32

BOOL GetFile(LPCTSTR lpRootPathName);

C#

函数声明:

[DllImport("kernel32.dll", CharSet = CharSet.Auto)]

static extern bool GetFile (

 [MarshalAs(UnmanagedType.LPTStr)]

 string rootPathName);

函数调用:

string pathname;

GetFile(pathname);

备注:

DllImport中的CharSet是为了说明自动地调用该函数相关的Ansi版本或者Unicode版本

 

变长字符串处理:

C#

函数声明:

[DllImport("kernel32.dll", CharSet = CharSet.Auto)]

public static extern int GetShortPathName(

  [MarshalAs(UnmanagedType.LPTStr)]

  string path,

  [MarshalAs(UnmanagedType.LPTStr)]

  StringBuilder shortPath,

  int shortPathLength);

函数调用:

StringBuilder shortPath = new StringBuilder(80);

int result = GetShortPathName(

@"d:\test.jpg", shortPath, shortPath.Capacity);

string s = shortPath.ToString();

struct

具有内嵌字符数组的结构:

Win32

typedef struct _TIME_ZONE_INFORMATION {

  LONG    Bias;

  WCHAR   StandardName[ 32 ];

  SYSTEMTIME StandardDate;

  LONG    StandardBias;

  WCHAR   DaylightName[ 32 ];

  SYSTEMTIME DaylightDate;

  LONG    DaylightBias;

} TIME_ZONE_INFORMATION, *PTIME_ZONE_INFORMATION;

C#

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]

struct TimeZoneInformation

{

  public int bias;

  [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 32)]

  public string standardName;

  SystemTime standardDate;

  public int standardBias;

  [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 32)]

  public string daylightName;

  SystemTime daylightDate;

  public int daylightBias;

}

具有回调的函数

Win32

BOOL EnumDesktops(

 HWINSTA hwinsta,       // 窗口实例的句柄

 DESKTOPENUMPROC lpEnumFunc, // 回调函数

 LPARAM lParam        // 用于回调函数的值

);

回调函数DESKTOPENUMPROC的声明:

BOOL CALLBACK EnumDesktopProc(

 LPTSTR lpszDesktop, // 桌面名称

 LPARAM lParam    // 用户定义的值

);

C#

将回调函数的声明转化为委托:

delegate bool EnumDesktopProc(

 [MarshalAs(UnmanagedType.LPTStr)]

  string desktopName,

  int lParam);

该函数在C#中的声明:

[DllImport("user32.dll", CharSet = CharSet.Auto)]
static extern bool EnumDesktops(
  IntPtr windowStation,
  EnumDesktopProc callback,
  int lParam);

该表对C#中调用win32函数,以及c++编写的dll时参数及返回值的转换做了一个小的总结,如果想进一步了解这方面内容的话,可以参照msdn中“互操作封送处理”一节。

引自:http://blog.csdn.net/xiaochongchong1248/archive/2010/01/12/5181345.aspx

例子:

/// <summary>
/// 定义结构体
/// </summary>
public struct UUID2
{
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 37)]
    public string szID;
}


/// <summary>
/// 声明非托管代码中的方法
/// </summary>
/// <param name="username">用户名</param>
/// <param name="uId">用户编号</param>
/// <returns>标志位 1-成功 0-没有此用户 -1-失败</returns>
[DllImport("Camnpr.dll", EntryPoint = "GetUserID", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.Cdecl)]
public static extern Int32 GetUserID(string username, ref UUID2 uId);

/// <summary>
/// 根据用户名获取用户编号
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnGetUserID_Click(object sender, EventArgs e)
{
    string strPhoneNo = tbPhoneNO.Text.Trim();

    UUID2 uId = new UUID2();
    Int32 iReturn = GetUserID("camnpr", ref uId);

    if (iReturn > 0)
    {
        tbUserID.Text = uId.szID;
    }
    else
    {
        MessageBox.Show(iReturn.ToString());
    }
}

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