c# - c#中如何获取Marshal的值

Question

我有以下几行代码:

public static string getTrack1(string track1, int len)
{
  IntPtr track1Ptr = UnsafeNativeMethods.Decrypt(track1, len);
  Byte[] track1b = new Byte[200];
  Marshal.Copy(track1Ptr, track1b, 0, track1b.Length);
   return track1b.ToString();
}

解密方法的减速是:

internal static class UnsafeNativeMethods
{
  [DllImport(_dllLocation, CallingConvention = CallingConvention.Cdecl)]
  public static extern IntPtr Decrypt(string track1, int dataLen);
 }

我正在从 visual c++ 代码返回 unsigned char* 并且每当我从 c# 代码调用 dll 时它总是返回“System.Byte[]"而不是值。我在 marshal 中做错了什么吗？

请帮帮我

Answer 1

您错过了从 byte[] 到 string 的转换，但您必须定义什么是编码。这可能有效:

public static string getTrack1(string track1, int len)
{
  IntPtr track1Ptr = UnsafeNativeMethods.Decrypt(track1, len);
  Byte[] track1b = new Byte[200];
  Marshal.Copy(track1Ptr, track1b, 0, track1b.Length);
   return Encoding.Default.GetString(track1b);
}

但这样做会更好；

public static string getTrack1(string track1, int len)
{
  IntPtr track1Ptr = UnsafeNativeMethods.Decrypt(track1, len);
  return Marshal.PtrToStringAnsi(track1Ptr);
}

如果编码是 Ansi(=默认)