CSharp如何调用dll中带指针参数.docx

C#调用C+DLL的方法，不同参数类型的调用方法1. 参数为基本类型，例如int, float, char等C+void fun(int value);void fun(float vaue);void fun(char ch);C#DllImport(xxx.dll)public static extern void fun(Int32 value);DllImport(xxx.dll)public static extern void fun(float value);DllImport(xxx.dll)public static extern void fun(char ch);2. 参数为基本类型 + 指针， 例如int*, float*, char*等C+void fun(int* value);void fun(float* vaue);void fun(char* ch);C#DllImport(xxx.dll)public static extern void fun(ref Int32 value);DllImport(xxx.dll)public static extern void fun(ref float value);参数为char*，在C#中有几种实现方式A. public static extern void fun(string ch);/ch内容不会改变B. public static extern void fun(StringBuilder ch);/ch内容会改变3. 参数为结构体C+struct pointint value;/基本类型char ch;/基本类型int number100;/数组char buffer100;/字符串数组;void fun(point pt);C#StructLayout(LayoutKind.Sequential)public struct pointpublic Int32 value;public char ch;MarshalAs(UnmanagedType.ByValArray, SizeConst = 100)public Int32 number;MarshalAs(UnmanagedType.ByValTStr, SizeConst = 100)public char buffer;DllImport(xxx.dll)public static extern void fun(point pt);4. 参数为结构体指针C+void fun(point* pt);C#DllImport(xxx.dll)public static extern void fun(ref point pt);5. 参数为结构体， 并且结构体还嵌套结构体C+struct pointint value;/基本类型char ch;/基本类型int number100;/数组char buffer100;/字符串数组struct point pt;/嵌套结构体;void fun(point pt);C#StructLayout(LayoutKind.Sequential)public struct pointpublic Int32 value;public char ch;MarshalAs(UnmanagedType.ByValArray, SizeConst = 100)public Int32 number;MarshalAs(UnmanagedType.ByValTStr, SizeConst = 100)public char buffer;public point pt;DllImport(xxx.dll)public static extern void fun(point pt);6. 参数为结构体， 并且结构体还嵌套结构体指针或者双指针C+struct pointint value;/基本类型char ch;/基本类型int number100;/数组char buffer100;/字符串数组struct point* p1;/嵌套结构体指针struct point* p2;/嵌套结构体双指针;void fun(point pt);C#StructLayout(LayoutKind.Sequential)public struct pointpublic Int32 value;public char ch;MarshalAs(UnmanagedType.ByValArray, SizeConst = 100)public Int32 number;MarshalAs(UnmanagedType.ByValTStr, SizeConst = 100)public char buffer;public IntPtr p1;/使用IntPtr替代嵌套指针public IntPtr p2;/使用IntPtr替代嵌套指针DllImport(xxx.dll)public static extern void fun(point pt);由于嵌套指针的使用比较复杂，需要借助一些手段才能够确保正常调用DLL方法C#class ProgramStructLayout(LayoutKind.Sequential)public struct pointpublic Int32 value;public char ch;MarshalAs(UnmanagedType.ByValArray, SizeConst = 100)public Int32 number;MarshalAs(UnmanagedType.ByValTStr, SizeConst = 100)public char buffer;public IntPtr p1;/使用IntPtr替代嵌套指针public IntPtr p2;/使用IntPtr替代嵌套指针DllImport(xxx.dll)public static extern void fun(point pt);static void Main(string args)point pt = new point();pt.p1 = Marshal.AllocHGlobal(Marshal.Sizeof(typeof(point);pt.p2 = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(point) * 2);trypt.value = 1; /实现给p1赋值point ptt = new point(); ptt.value = 1; Marshal.StructureToPtr(ptt, pt.p1, false);/实现给p2赋值/由于双指针不能够直接传值，需要用到中间结构的数组指针IntPtr ptr = new IntPtr2;ptr0 = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(point);ptr1 = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(point);tryMarshal.StructureToPtr(ptt, ptr0, false);Marshal.Copy(ptr, 0, pt.p2, 2);fun(pt);/测试返回的指针值是否正确ptt = (point)Marshal.PtrToStructure(pt.p1, typeof(point);Marshal.Copy(pt.p2, ptr, 0, 2);ptt = (point)Marshal.PtrToStructure(ptr0, typeof(point);ptt = (point)Marshal.PtrToStructure(ptr1, typeof(point);catch(System.Exception e)string str = e.M