Marshal.Copy在对有C++代码和C#代码混合的项目中很有用，它能在非托管指针和托管数组间起到相互转换作用。

Namespace: System.Runtime.InteropServices
Assembly: mscorlib (in mscorlib.dll)

Copies data from a managed array to an unmanaged memory pointer, or from an unmanaged memory pointer to a managed array.
把数据从一个托管的数组拷贝到一个非托管的内存指针， 或从一个非托管的内存指针拷贝到一个托管的数组。

Marchal.Copy有很多形态，其四个参数有很多类型变化：

Copy(array<Byte>[]()[], Int32, IntPtr, Int32)
Copy(array<Char>[]()[], Int32, IntPtr, Int32)
Copy(array<Double>[]()[], Int32, IntPtr, Int32)
Copy(array<Int16>[]()[], Int32, IntPtr, Int32)
Copy(array<Int32>[]()[], Int32, IntPtr, Int32)
Copy(array<Int64>[]()[], Int32, IntPtr, Int32)
Copy(IntPtr, array<Byte>[]()[], Int32, Int32)
Copy(IntPtr, array<Char>[]()[], Int32, Int32)
Copy(IntPtr, array<Double>[]()[], Int32, Int32)
Copy(IntPtr, array<Int16>[]()[], Int32, Int32)
Copy(IntPtr, array<Int32>[]()[], Int32, Int32)
Copy(IntPtr, array<Int64>[]()[], Int32, Int32)
Copy(IntPtr, array<IntPtr>[]()[], Int32, Int32)
Copy(IntPtr, array<Single>[]()[], Int32, Int32)
Copy(array<IntPtr>[]()[], Int32, IntPtr, Int32)
Copy(array<Single>[]()[], Int32, IntPtr, Int32)

一个项目中有一个USB应用，代码是C++，用到了指针，而到C#代码中，需要将指针内存的数据拷贝到数组中，我用的简单代码如下：

源 (source)： byte* ReceiveData
目的(target)： byte[] arrRecData
长度(length): ReceiveLength

//The following 2 lines code just for debug — copy point to array
byte[] arrRecData = new byte[(int)ReceiveLength];
Marshal.Copy((IntPtr)ReceiveData, arrRecData, 0, (int)ReceiveLength);

这样可以在C#中安全使用arrRecData数组了。