C++中调用的代码，可以正常实现：
//PCO_SensorInfo 是一个结构体
PCO_SensorInfo strsensorinf;
memset((void*)&strsensorinf.wSize, 0, sizeof(PCO_SensorInfo));
strsensorinf.wSize = sizeof(PCO_SensorInfo);// Set size of structure
strsensorinf.iConversionFactor = 8; // Set conversion factor of camera
strsensorinf.iDarkOffset = 32; // Set dark offset of camera
strsensorinf.iDataBits = 12; // Set bit resolution of camera
//// Set color type and alignment of image data.
strsensorinf.iSensorInfoBits = CONVERT_SENSOR_COLORIMAGE;// Set color camera type;
m_hLut = NULL; //m_hLut 是void* 型的
//调用dll
int err = PCO_ConvertCreate(&m_hLut, (PCO_SensorInfo*)&strsensorinf.wSize, 2);
C++ dll
int PCOCONVERT_API PCO_ConvertCreate(HANDLE* ph, PCO_SensorInfo *strSensor, int iConvertType);
上面可以正常实现！
C#代码：
CSharpDemo.sc2_cam.PCO_SensorInfo strsensorinf = new sc2_cam.PCO_SensorInfo();
strsensorinf.wSize =(ushort)(Marshal.SizeOf(typeof(CSharpDemo.sc2_cam.PCO_SensorInfo)));// Set size of structure
strsensorinf.iConversionFactor = 8; // Set conversion factor of camera
strsensorinf.iDarkOffset = 32; // Set dark offset of camera
strsensorinf.iDataBits = 12; // Set bit resolution of camera
//Set color type and alignment of image data.
strsensorinf.iSensorInfoBits = 1;// Set color camera type;
strsensorinf.dwzzDummy1 = new uint[38];
m_hLut = new IntPtr();
//这里该怎么调用？
int err = sc2_cam.PCO_ConvertCreate(ref m_hLut, ref strsensorinf, 2);
C#dll:
[DllImport("PCO_Conv.dll", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true)]
public static extern int PCO_ConvertCreate(ref IntPtr hdriver, ref PCO_SensorInfo sensorInfo, int iConvertType); (这样引用对吗？)上述C++代码是可以正常调用的！请大家指教一下，看看C#的地方怎么弄？总是调用不成功！先谢过了！
------解决方案--------------------
前提是要先把PCO_Conv.dll给注册了
------解决方案--------------------
这个不好说，必须有导出函数的原型才知道。
另外是不是调用约定搞错了，默认是stdcall的，你的C++默认是cdecl的。
贴出具体的错误信息。
------解决方案--------------------
没注意到你是传结构
这样就要修改一下了?
如下?
[StructLayout(LayoutKind.Sequential)]
public struct PCO_SensorInfo
{
...
// 你的定义
}
[DllImport("PCO_Conv.dll", EntryPoint = "PCO_ConvertCreate", CharSet = CharSet.Ansi)]
public static extern int PCO_ConvertCreate(IntPtr hdriver, ref PCO_SensorInfo sensorInfo, int iConvertType);
};