extern "C" __declspec(dllexport) char* WINAPI base64_decode( char *data,char base[])

{

}

private void Form1_Load(object sender, EventArgs e)

{

    IntPtr ptrIn1 = Marshal.StringToHGlobalAnsi("这是一个中文base64加密的测试");

    IntPtr ptrIn2 = Marshal.StringToHGlobalAnsi("01234abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ56789+/=");

    IntPtr ptrIn3 = base64_encode(ptrIn1, ptrIn2);

    string retlust1 = Marshal.PtrToStringAnsi(ptrIn3);

    IntPtr ptrIn4 = Marshal.StringToHGlobalAnsi(retlust1);

    IntPtr ptrIn5 = Marshal.StringToHGlobalAnsi("01234abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ56789+/=");

    IntPtr ptrIn6 = base64_decode(ptrIn4, ptrIn5);

    string retlust2 = Marshal.PtrToStringAnsi(ptrIn6);

}

[DllImport("FwBase64.dll")]

private static extern IntPtr base64_encode(IntPtr a, IntPtr b);

[DllImport("FwBase64.dll")]

private static extern IntPtr base64_decode(IntPtr a, IntPtr b);