C#访问C++DLL文件
1.首先把要调用的DLL文件拷贝到你编译以后的debug文件下，如图：
2.定义要访问的方法或者变量，在程序中加载要调用的DLL文件，如图：
上述方法在C++中的定义如下：
3.然后调用定义过的方法即可：
这就完成了对C++DLL的调用。
4.C#调用C++编写的DLL函数各种参数传递问题：
1. 不返回值的参数
C++ 原型:
bool SendNewSms(char *szTel, char *szMessage);
C#引用;
[DllImport( "CdmaCard.dll",EntryPoint="SendNewSms")]
public static extern bool SendNewSms(string phone,string msg);
2. 带返回值(char *)
C++原型:
BOOL GetCardErrorMessage(char *szErrorMessage , int errorCode);
C#引用
[DllImport( "CdmaCard.dll",EntryPoint="GetCardErrorMessage")]
public static extern int GetCardErrorMessage(StringBuilder msg,int errorCode);
StringBuilder buf = new StringBuilder(1024);//指定的Buf大小必须大于可能的最大长度
GetCardErrorMessage(buf,1);
3. 带返回值(其他类型)
C++原型:
BOOL GetSmsSaveStation (int *nSmsStation);
C#引用
[DllImport( "CdmaCard.dll",EntryPoint="GetSmsSaveStation")]
public static extern bool GetSmsSaveStation(ref int nStation);
4. 传递结构体指针(C++填充)
C++原型:
struct NET_INFO_STRUCT
{
DWORD nDurationTime; //持续时间
double nReceiveByte; //接收字节
double nSendByte; //发送字节
};
BOOL NetGetConnectDetail(NET_INFO_STRUCT *lpNetInfo);
C#引用
public struct NET_INFO_STRUCT
{
public uint nDurationTime; //持续时间
public double nReceiveByte; //接收字节
public double nSendByte; //发送字节
}
[DllImport( "CdmaCard.dll",EntryPoint="NetGetConnectDetail")]
public static extern int NetGetConnectDetail(ref NET_INFO_STRUCT pNetInfo);
NET_INFO_STRUCT netInfo = new NET_INFO_STRUCT();
NetGetConnectDetail(ref netInfo);
5. 传递结构体数组(C++来填充)
C++原型:
struct UIM_BOOK_STRUCT
{
int UimIndex;
char szName[15];
char szPhone[21];
};
int ReadUimAllBook(UIM_BOOK_STRUCT lpUimBookItem[],int nMaxArraySize);
C#引用
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]//可以指定编码类型
public struct UIM_BOOK_STRUCT
{
public int UimIndex;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst= 15)]
public string szName;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst= 21)]
public string szPhone;
};
[DllImport( "CdmaCard.dll",EntryPoint="ReadUimAllBook")]
public static extern int ReadUimAllBook([Out] UIM_BOOK_STRUCT [] lpUimBookItem,int nMaxArraySize);
UIM_BOOK_STRUCT[] p = new UIM_BOOK_STRUCT[20];
int ret = ReadUimAllBook(p,p.Length);
6. 注意问题
类型不一致,会导致调用失败,
(1) long 类型,在C++中是4字节的整数,在C#中是8字节的整数;
(2) 字符串类型的设置不正确;
以下是几个简单的window调用
[System.Security.SuppressUnmanagedCodeSecurity] // We won't use this maliciously
[DllImport("User32.dll", CharSet=CharSet.Auto)]
public static extern bool ScreenToClient(IntPtr hWnd, ref System.Drawing.Point rect);
[System.Security.SuppressUnmanagedCodeSecurity] // We won't use this maliciously
[DllImport("User32.dll", CharSet=CharSet.Auto)]
public static extern bool GetWindowRect(IntPtr hWnd, out System.Drawing.Rectangle rect);
[System.Security.SuppressUnmanagedCodeSecurity] // We won't use this maliciously
[DllImport("User32.dll", CharSet=CharSet.Auto)]
public static extern bool UnregisterClass([MarshalAs(UnmanagedType.LPTStr)] string className, IntPtr instanceHandle);
5.对于C++中的类型在C#中有如下的映射：
//C++中的DLL函数原型为
//extern "C" __declspec(dllexport) bool 方法名一(const char* 变量名1, unsigned char* 变量名2)
//extern "C" __declspec(dllexport) bool 方法名二(const unsigned char* 变量名1, char* 变量名2)
//C#调用C++的DLL搜集整理的所有数据类型转换方式,可能会有重复或者多种方案,自己多测试
//c++:HANDLE(void *) ---- c#:System.IntPtr
//c++:Byte(unsigned char) ---- c#:System.Byte
//c++:SHORT(short) ---- c#:System.Int16
//c++:WORD(unsigned short) ---- c#:System.UInt16
//c++:INT(int) ---- c#:System.Int16
//c++:INT(int) ---- c#:System.Int32
//c++:UINT(unsigned int) ---- c#:System.UInt16
//c++:UINT(unsigned int) ---- c#:System.UInt32
//c++:LONG(long) ---- c#:System.Int32
//c++:ULONG(unsigned long) ---- c#:System.UInt32
//c++:DWORD(unsigned long) ---- c#:System.UInt32
//c++:DECIMAL ---- c#:System.Decimal
//c++:BOOL(long) ---- c#:System.Boolean
//c++:CHAR(char) ---- c#:System.Char
//c++:LPSTR(char *) ---- c#:System.String
//c++:LPWSTR(wchar_t *) ---- c#:System.String
//c++:LPCSTR(const char *) ---- c#:System.String
//c++:LPCWSTR(const wchar_t *) ---- c#:System.String
//c++:PCAHR(char *) ---- c#:System.String
//c++:BSTR ---- c#:System.String
//c++:FLOAT(float) ---- c#:System.Single
//c++:DOUBLE(double) ---- c#:System.Double
//c++:VARIANT ---- c#:System.Object
//c++:PBYTE(byte *) ---- c#:System.Byte[]
//c++:BSTR ---- c#:StringBuilder
//c++:LPCTSTR ---- c#:StringBuilder
//c++:LPCTSTR ---- c#:string
//c++:LPTSTR ---- c#:[MarshalAs(UnmanagedType.LPTStr)] string
//c++:LPTSTR 输出变量名 ---- c#:StringBuilder 输出变量名
//c++:LPCWSTR ---- c#:IntPtr
//c++:BOOL ---- c#:bool
//c++:HMODULE ---- c#:IntPtr
//c++:HINSTANCE ---- c#:IntPtr
//c++:结构体 ---- c#:public struct 结构体{};
//c++:结构体 **变量名 ---- c#:out 变量名 //C#中提前申明一个结构体实例化后的变量名
//c++:结构体 &变量名 ---- c#:ref 结构体 变量名
//c++:WORD ---- c#:ushort
//c++:DWORD ---- c#:uint
//c++:DWORD ---- c#:int
//c++:UCHAR ---- c#:int
//c++:UCHAR ---- c#:byte
//c++:UCHAR* ---- c#:string
//c++:UCHAR* ---- c#:IntPtr
//c++:GUID ---- c#:Guid
//c++:Handle ---- c#:IntPtr
//c++:HWND ---- c#:IntPtr
//c++:DWORD ---- c#:int
//c++:COLORREF ---- c#:uint
//c++:unsigned char ---- c#:byte
//c++:unsigned char * ---- c#:ref byte
//c++:unsigned char * ---- c#:[MarshalAs(UnmanagedType.LPArray)] byte[]
//c++:unsigned char * ---- c#:[MarshalAs(UnmanagedType.LPArray)] Intptr
//c++:unsigned char & ---- c#:ref byte
//c++:unsigned char 变量名 ---- c#:byte 变量名
//c++:unsigned short 变量名 ---- c#:ushort 变量名
//c++:unsigned int 变量名 ---- c#:uint 变量名
//c++:unsigned long 变量名 ---- c#:ulong 变量名
//c++:char 变量名 ---- c#:byte 变量名 //C++中一个字符用一个字节表示,C#中一个字符用两个字节表示
//c++:char 数组名[数组大小] ---- c#:MarshalAs(UnmanagedType.ByValTStr, SizeConst = 数组大小)] public string 数组名; ushort
//c++:char * ---- c#:string //传入参数
//c++:char * ---- c#:StringBuilder//传出参数
//c++:char *变量名 ---- c#:ref string 变量名
//c++:char *输入变量名 ---- c#:string 输入变量名
//c++:char *输出变量名 ---- c#:[MarshalAs(UnmanagedType.LPStr)] StringBuilder 输出变量名
//c++:char ** ---- c#:string
//c++:char **变量名 ---- c#:ref string 变量名
//c++:const char * ---- c#:string
//c++:char[] ---- c#:string
//c++:char 变量名[数组大小] ---- c#:[MarshalAs(UnmanagedType.ByValTStr,SizeConst=数组大小)] public string 变量名;
//c++:struct 结构体名 *变量名 ---- c#:ref 结构体名 变量名
//c++:委托 变量名 ---- c#:委托 变量名
//c++:int ---- c#:int
//c++:int ---- c#:ref int
//c++:int & ---- c#:ref int
//c++:int * ---- c#:ref int //C#中调用前需定义int 变量名 = 0;
//c++:*int ---- c#:IntPtr
//c++:int32 PIPTR * ---- c#:int32[]
//c++:float PIPTR * ---- c#:float[]
//c++:double** 数组名 ---- c#:ref double 数组名
//c++:double*[] 数组名 ---- c#:ref double 数组名
//c++:long ---- c#:int
//c++:ulong ---- c#:int
//c++:UINT8 * ---- c#:ref byte //C#中调用前需定义byte 变量名 = new byte();
//c++:handle ---- c#:IntPtr
//c++:hwnd ---- c#:IntPtr
//c++:void * ---- c#:IntPtr
//c++:void * user_obj_param ---- c#:IntPtr user_obj_param
//c++:void * 对象名称 ---- c#:([MarshalAs(UnmanagedType.AsAny)]Object 对象名称
//c++:char, INT8, SBYTE, CHAR ---- c#:System.SByte
//c++:short, short int, INT16, SHORT ---- c#:System.Int16
//c++:int, long, long int, INT32, LONG32, BOOL , INT ---- c#:System.Int32
//c++:__int64, INT64, LONGLONG ---- c#:System.Int64
//c++:unsigned char, UINT8, UCHAR , BYTE ---- c#:System.Byte
//c++:unsigned short, UINT16, USHORT, WORD, ATOM, WCHAR , __wchar_t ---- c#:System.UInt16
//c++:unsigned, unsigned int, UINT32, ULONG32, DWORD32, ULONG, DWORD, UINT ---- c#:System.UInt32
//c++:unsigned __int64, UINT64, DWORDLONG, ULONGLONG ---- c#:System.UInt64
//c++:float, FLOAT ---- c#:System.Single
//c++:double, long double, DOUBLE ---- c#:System.Double
//Win32 Types ---- CLR Type
//Struct需要在C#里重新定义一个Struct
//CallBack回调函数需要封装在一个委托里，delegate static extern int FunCallBack(string str);
//unsigned char** ppImage替换成IntPtr ppImage
//int& nWidth替换成ref int nWidth
//int*, int&, 则都可用 ref int 对应
//双针指类型参数，可以用 ref IntPtr
//函数指针使用c++: typedef double (*fun_type1)(double); 对应 c#:public delegate double fun_type1(double);
//char* 的操作c++: char*; 对应 c#:StringBuilder;
//c#中使用指针:在需要使用指针的地方 加 unsafe
//unsigned char对应public byte
/*
* typedef void (*CALLBACKFUN1W)(wchar_t*, void* pArg);
* typedef void (*CALLBACKFUN1A)(char*, void* pArg);
* bool BIOPRINT_SENSOR_API dllFun1(CALLBACKFUN1 pCallbackFun1, void* pArg);
* 调用方式为
* [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
* public delegate void CallbackFunc1([MarshalAs(UnmanagedType.LPWStr)] StringBuilder strName, IntPtr pArg);
*
*
*/
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