问C#调用C++ dll尝试读取或写入受保护的内存

EN

    Logon(BSTR DirectoryPath, BSTR ErrorFile, int Lang)

public partial class MainWindow : Window
{
    [DllImport("kernel32.dll")]
    static extern IntPtr LoadLibrary(string dllToLoad);

    [DllImport("kernel32.dll", CharSet = CharSet.Ansi, ExactSpelling = true, SetLastError = true)]
    public static extern IntPtr GetProcAddress(IntPtr hModule, string procedureName);

    [UnmanagedFunctionPointer(CallingConvention.Winapi)]
    private delegate int Logon([MarshalAs(UnmanagedType.BStr)]String DirectoryPath, [MarshalAs(UnmanagedType.BStr)]String ErrorFile, int Lang);

    public MainWindow()
    {
        InitializeComponent();

        try
        {

            string LnkPsbEppPath = "dll/LnkPsbEpp.dll";
            IntPtr pAddressFctLogon = GetProcAddress(LnkPsbEppLink, "@Tdtm_Dossier@Logon$qv"); 
            if (pAddressFctLogon == IntPtr.Zero)
                Console.WriteLine("Logon function not found");
            else
            {   
                try
                {
                    dynamic logon = Marshal.GetDelegateForFunctionPointer(pAddressFctLogon, typeof(Logon));
                    dynamic varLogon = logon(directoryPath, errorFilePath, 2); // <-- Here is where the AccessViolactionException happend
                }
                catch (Exception ex)
                {

                }
            }

        }
        catch (Exception ex)
        {
            Console.WriteLine("ERROR : " + ex.Message);
        }

    }
}