C#调用C++的方法

网上有很多C#调用C++的帖子，我之前走了不少弯路，现总结出来希望大家少走一些弯路，如果有什么不对的地方，欢迎大家随时纠正~
1.建立一个project,令其输出格式为dll。
2. 对于每一个被dll 封装的函数，要写成如下格式，之后build，即可生成dll。

typedef struct _testStru
{
float x;
float y;
float z;
}testStru;

extern "C" __declspec(dllexport) testStru* testReturnStruct(){
testStru *stru = new testStru();
stru->x = 1.1;
stru->y = 1.2;
stru->z = 1.3;
return stru;
}

3.再新建一个project,调用刚刚生成了dll。定义一个nativemethod class,如下

class NativeMethod
{
[StructLayout(LayoutKind.Sequential, CharSet=CharSet.Unicode)]
public struct TestStru
{
public Single x;
public Single y;
public Single z;
};
[DllImport("NativeLibrary.dll", EntryPoint = "testReturnStruct")]
public static extern IntPtr testReturnStruct();

[DllImport("NativeLibrary.dll", EntryPoint = "testOutStruct")]
public static extern void testOutStruct(ref TestStru p);
}