Trying to get libmecab.dll (MeCab) to work with C#

public class Mecab
{
    [DllImport("libmecab.dll", CallingConvention = CallingConvention.Cdecl, CharSet=CharSet.Unicode)]
    private extern static IntPtr mecab_new2(string arg);
    [DllImport("libmecab.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Unicode)]
    private extern static IntPtr mecab_sparse_tostr(IntPtr m, byte[] str);
    [DllImport("libmecab.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Unicode)]
    private extern static void mecab_destroy(IntPtr m);

    public static String Parse(String input)
    {
        IntPtr mecab = mecab_new2("");
        IntPtr nativeStr = mecab_sparse_tostr(mecab, Encoding.UTF8.GetBytes(input));
        int size = nativeArraySize(nativeStr) - 1;
        byte[] data = new byte[size];
        Marshal.Copy(nativeStr, data, 0, size);

        mecab_destroy(mecab);

        return Encoding.UTF8.GetString(data);
    }

    private static int nativeArraySize(IntPtr ptr)
    {
        int size = 0;
        while (Marshal.ReadByte(ptr, size) > 0)
            size++;

        return size;
    }
}

public class Mecab
{
    [DllImport("libmecab.dll", CallingConvention = CallingConvention.Cdecl, CharSet=CharSet.Unicode)]
    private extern static IntPtr mecab_new2(string arg);
    [DllImport("libmecab.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Unicode)]
    private extern static IntPtr mecab_sparse_tostr(IntPtr m, byte[] str);
    [DllImport("libmecab.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Unicode)]
    private extern static void mecab_destroy(IntPtr m);

    public static String Parse(String input)
    {
        IntPtr mecab = mecab_new2("");
        IntPtr nativeStr = mecab_sparse_tostr(mecab, Encoding.UTF8.GetBytes(input));
        int size = nativeArraySize(nativeStr) - 1;
        byte[] data = new byte[size];
        Marshal.Copy(nativeStr, data, 0, size);

        mecab_destroy(mecab);

        return Encoding.UTF8.GetString(data);
    }

    private static int nativeArraySize(IntPtr ptr)
    {
        int size = 0;
        while (Marshal.ReadByte(ptr, size) > 0)
            size++;

        return size;
    }
}

public class Mecab
{
    [DllImport("libmecab.dll", CallingConvention = CallingConvention.Cdecl, CharSet=CharSet.Unicode)]
    private extern static IntPtr mecab_new2(string arg);
    [DllImport("libmecab.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Unicode)]
    private extern static IntPtr mecab_sparse_tostr(IntPtr m, byte[] str);
    [DllImport("libmecab.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Unicode)]
    private extern static void mecab_destroy(IntPtr m);

    public static String Parse(String input)
    {
        IntPtr mecab = mecab_new2("");
        IntPtr nativeStr = mecab_sparse_tostr(mecab, Encoding.UTF8.GetBytes(input));
        int size = nativeArraySize(nativeStr) - 1;
        byte[] data = new byte[size];
        Marshal.Copy(nativeStr, data, 0, size);

        mecab_destroy(mecab);

        return Encoding.UTF8.GetString(data);
    }

    private static int nativeArraySize(IntPtr ptr)
    {
        int size = 0;
        while (Marshal.ReadByte(ptr, size) > 0)
            size++;

        return size;
    }
}

public class Mecab
{
    [DllImport("libmecab.dll", CallingConvention = CallingConvention.Cdecl, CharSet=CharSet.Unicode)]
    private extern static IntPtr mecab_new2(string arg);
    [DllImport("libmecab.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Unicode)]
    private extern static IntPtr mecab_sparse_tostr(IntPtr m, byte[] str);
    [DllImport("libmecab.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Unicode)]
    private extern static void mecab_destroy(IntPtr m);

    public static String Parse(String input)
    {
        IntPtr mecab = mecab_new2("");
        IntPtr nativeStr = mecab_sparse_tostr(mecab, Encoding.UTF8.GetBytes(input));
        int size = nativeArraySize(nativeStr) - 1;
        byte[] data = new byte[size];
        Marshal.Copy(nativeStr, data, 0, size);

        mecab_destroy(mecab);

        return Encoding.UTF8.GetString(data);
    }

    private static int nativeArraySize(IntPtr ptr)
    {
        int size = 0;
        while (Marshal.ReadByte(ptr, size) > 0)
            size++;

        return size;
    }
}

public class Mecab
{
    [DllImport("libmecab.dll", CallingConvention = CallingConvention.Cdecl, CharSet=CharSet.Unicode)]
    private extern static IntPtr mecab_new2(string arg);
    [DllImport("libmecab.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Unicode)]
    private extern static IntPtr mecab_sparse_tostr(IntPtr m, byte[] str);
    [DllImport("libmecab.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Unicode)]
    private extern static void mecab_destroy(IntPtr m);

    public static String Parse(String input)
    {
        IntPtr mecab = mecab_new2("");
        IntPtr nativeStr = mecab_sparse_tostr(mecab, Encoding.UTF8.GetBytes(input));
        int size = nativeArraySize(nativeStr) - 1;
        byte[] data = new byte[size];
        Marshal.Copy(nativeStr, data, 0, size);

        mecab_destroy(mecab);

        return Encoding.UTF8.GetString(data);
    }

    private static int nativeArraySize(IntPtr ptr)
    {
        int size = 0;
        while (Marshal.ReadByte(ptr, size) > 0)
            size++;

        return size;
    }
}