C#调用非托管的DLL文件
写了段C#代码实现了调用C++写的非托管DLL
Access C++(unmanaged) APIs using C#
1 using System;
2 using System.IO;
3 using System.Collections.Generic;
4 using System.Text;
5 using System.Reflection;
6 using System.Reflection.Emit;
7 /*
8 The most important attributes of namespace System.Runtime.InteropServices are
9 DllImportAttribute, which you use to define platform invoke methods for accessing unmanaged APIs,
10 and MarshalAsAttribute, which you use to specify how data is marshaled between managed and unmanaged memory.
11 */
12 using System.Runtime.InteropServices;
13
14 namespace TransDLLProxyNameSpace
15 {
16 public struct SampleStruct
17 {
18 public Int32 value;
19 };
20
21 class TransDLLProxy
22 {
23 // Dynamic Call the export function of a Native DLL.
24
25 // Declare the external method firstly.
26
27 [DllImport("Kernel32")]
28 // Retrieve the address of an exported function or variable from the specified DLL.
29 public static extern int GetProcAddress(int handle, String funcname);
30
31 [DllImport("Kernel32")]
32 // Map the specified executable module into the address space of the calling process.
33 public static extern int LoadLibrary(String funcname);
34
35 [DllImport("Kernel32")]
36 // Decrement the reference count of the loaded DLL.
37 // When the reference count reaches zero, the module is unmapped from the address space of the calling process.
38 public static extern int FreeLibrary(int handle);
39
40 // Get the address of the function.
41 private static Delegate GetAddress(int dllModule, string funcName, Type t)
42 {
43 int addr = GetProcAddress(dllModule, funcName);
44
45 if (addr == 0)
46 return null;
47 else
48 //Convert an unmanaged function pointer to a delegate.
49 return Marshal.GetDelegateForFunctionPointer(new IntPtr(addr), t);
50 }
51
52 //DLL function pointers.
53 private delegate int DLL_GPFunc(string inStr);
54 private delegate int DLL_SPFunc(ref StringBuilder outStr);
55 private delegate int DLL_TransFunc(IntPtr header, byte[] inArray, Int32 inLength, ref IntPtr outPtr, ref Int32 outLength);
56 private delegate int DLL_Release();
57 //A handle to the DLL module that contains the function or variable.
58 private int m_hModule;
59 private DLL_GPFunc m_pGPFunc;
60 private DLL_SPFunc m_pSPFunc;
61 private DLL_TransFunc m_pTransFunc;
62 private DLL_Release m_pRelease;
63
64 //Constructor
65 public TransDLLProxy()
66 {
67 m_hModule = 0;
68 m_pGPFunc = null;
69 m_pSPFunc = null;
70 m_pTransFunc = null;
71 m_pRelease = null;
72 }
73 ~TransDLLProxy()
74 {
75 UnloadDLL();
76 }
77
78 //Load DLL.
79 public bool LoadDLL(string strDllName)
80 {
81 //Release handle firstly.
82 if (m_hModule != 0)
83 {
84 Release();
85 }
86 //Get the handle to the DLL module.
87 m_hModule = LoadLibrary(strDllName);
88 if (m_hModule == 0)
89 {
90 return false;
91 }
92 //Get the address of the function.
93 m_pGPFunc = (DLL_GPFunc)GetAddress(m_hModule, "GPFunc", typeof(DLL_GPFunc));
94 m_pSPFunc = (DLL_SPFunc)GetAddress(m_hModule, "SPFunc", typeof(DLL_SPFunc));
95 m_pTransFunc = (DLL_TransFunc)GetAddress(m_hModule, "TransFunc", typeof(DLL_TransFunc));
96 m_pRelease = (DLL_Release)GetAddress(m_hModule, "Release", typeof(DLL_Release));
97 return true;
98 }
99
100 //Unload DLL.
101 public void UnloadDLL()
102 {
103 if (m_hModule != 0)
104 {
105 FreeLibrary(m_hModule);
106 m_hModule = 0;
107 }
108 }
109
110 //Proxy Functions
111
112 //Call DLL interface with getting parameters.
113 public int GPFunc(string inStr)
114 {
115 if (m_hModule == 0|| m_pGPFunc == null)
116 {
117 return -1;
118 }
119 return m_pGPFunc(inStr);
120 }
121 //Call DLL interface with setting parameters.
122 public int SPFunc(ref string outStr)
123 {
124 if (m_hModule == 0 || m_pSPFunc == null)
125 {
126 return -1;
127 }
128 StringBuilder tStr;
129 tStr = new StringBuilder(256);
130 int nResult = m_pHelp(tStr);
131 outStr = tStr.ToString();
132 return nResult;
133 }
134 //Call DLL interface to transfer struct.
135 public int TransFunc(SampleStruct header, MemoryStream instream, ref MemoryStream outstream)
136 {
137 if (m_hModule == 0 || m_pTransFunc == null)
138 {
139 return -1;
140 }
141
142 // Create a managed array.
143 byte[] managedArray = null;
144 int length = 0;
145 //Assume that instream.Length == outstream.Length.
146 IntPtr ptrOut = Marshal.AllocHGlobal((int)(instream.Length));
147 IntPtr pHeader = Marshal.AllocHGlobal(Marshal.SizeOf(header));
148
149 try
150 {
151 Marshal.StructureToPtr(header, pHeader, true);
152 int nResult = m_pTransFunc(pHeader, instream.ToArray(), (int)(instream.Length), ref ptrOut, ref length);
153 if (nResult == 0 && length != 0)
154 {
155 managedArray = new byte[length];
156 /*Copy data from a managed array to an unmanaged memory pointer,
157 or from an unmanaged memory pointer to a managed array. */
158 Marshal.Copy(ptrOut, managedArray, 0, length * sizeof(byte));
159 outstream.Write(managedArray, 0, length);
160 // Free the unmanaged memory.
161 Marshal.FreeHGlobal(ptrOut);
162 ptrOut = IntPtr.Zero;
163 }
164 }
165 finally
166 {
167 Marshal.FreeHGlobal(pHeader);
168 pHeader = IntPtr.Zero;
169 }
170 return nResult;
171 }
172 // Release the Resources.
173 public int Release()
174 {
175 if (m_hModule == 0 || m_pRelease == null)
176 {
177 return -1;
178 }
179 return m_pRelease();
180 }
181 }
182 }
---------------------------------------------
System.Runtime.InteropServices Namespace
http://msdn.microsoft.com/en-us/library/9esea608%28v=VS.80%29.aspx
MinGW下DLL编写与调用
http://tingxx.ycool.com/post.2023760.html
MinGW中定义DLL
http://blog.sina.com.cn/s/blog_4ac2a65901000brf.html
VC++动态链接库(DLL)编程深入浅出
http://pcedu.pconline.com.cn/empolder/gj/vc/0509/699672.html
在C#中动态调用native dll的导出函数
http://dotnet.chinaitlab.com/CSharp/727142.html
C#调用C++的DLL
http://www.cnblogs.com/virusswb/archive/2008/05/30/1210520.html
Delegate比较全面的例子(原创)
http://www.cnblogs.com/idior/articles/100666.html
如何：创建和使用 C# DLL（C# 编程指南）
http://msdn.microsoft.com/zh-cn/library/3707x96z(VS.80).aspx
在VC中创建DLL文件的方法步骤
http://dev.yesky.com/475/7667475.shtml
