C#调用C++DLL传递结构体数组的终极解决方案
在项目开发时，要调用C++封装的DLL，普通的类型C#上一般都对应，只要用DllImport传入从DLL中引入函数就可以了。但是当传递的是结构体、结构体数组或者结构体指针的时候，就会发现C#上没有类型可以对应。这时怎么办，第一反应是C#也定义结构体，然后当成参数传弟。然而，当我们定义完一个结构体后想传递参数进去时，会抛异常，或者是传入了结构体，但是返回值却不是我们想要的，经过调试跟踪后发现，那些值压根没有改变过，代码如下。
[DllImport("workStation.dll")] private static extern bool fetchInfos(IntPtr infosIntPtr); [DllImport("workStation.dll")] private static extern bool fetchInfos(byte[] infos); [StructLayoutAttribute(LayoutKind.Sequential, CharSet = CharSet.Ansi, Pack = 1)] public struct Info { public int OrderNO; [MarshalAs(UnmanagedType.ByValArray, SizeConst = 32)] public byte[] UniqueCode; public float CpuPercent; }; private void buttonTest_Click(object sender, EventArgs e) { try { int count = 128; int size = Marshal.SizeOf(typeof(Info)); byte[] inkInfosBytes = new byte[count * size]; if (fetchInfos(inkInfosBytes)) { MessageBox.Show("Fail"); return; } Info[] infos = new Info[count]; for (int inkIndex = 0; inkIndex < count; inkIndex++) { byte[] inkInfoBytes = new byte[size]; Array.Copy(inkInfosBytes, inkIndex * size, inkInfoBytes, 0, size); infos[inkIndex] = (Info)bytesToStruct(inkInfoBytes, typeof(Info)); } string message = ""; foreach (Info info in infos) { message += string.Format("OrderNO={0}\r\nUniqueCode={1}\r\nCpu={2}", info.OrderNO, Encoding.UTF8.GetString(info.UniqueCode), info.CpuPercent ); } MessageBox.Show(message); } catch (System.Exception ex) { MessageBox.Show(ex.Message); } } #region bytesToStruct /// <summary> /// Byte array to struct or classs. /// </summary> /// <param name=”bytes”>Byte array</param> /// <param name=”type”>Struct type or class type. /// Egg:class Human{...}; /// Human human=new Human(); /// Type type=human.GetType();</param> /// <returns>Destination struct or class.</returns> public static object bytesToStruct(byte[] bytes, Type type) { int size = Marshal.SizeOf(type);//Get size of the struct or class. if (bytes.Length < size) { return null; } IntPtr structPtr = Marshal.AllocHGlobal(size);//Allocate memory space of the struct or class. Marshal.Copy(bytes, 0, structPtr, size);//Copy byte array to the memory space. object obj = Marshal.PtrToStructure(structPtr, type);//Convert memory space to destination struct or class. Marshal.FreeHGlobal(structPtr);//Release memory space. return obj; } #endregion对于实在想不到要怎么传数据的时候，可以考虑byte数组来传(即便是整型也可以，只要是开辟4字节(在32位下))，只要开的长度对应的上，在拿到数据后，要按类型规则转换成所要的数据，一般都能达到目的。