C# 调用C写的DLL时 对应的char* 类型转化为 ref byte

C中代码：

string name = @"d:\result\Gaussian_6_0.3.jpg";            byte[] filename = new byte[100];            for (int i = 0; i < name.Length; i++)            {                filename[i] = (byte)name[i];            }            liblept168.read(ref filename[0]);