internal partial class CredentialsFormHelper : Form
    {
        public string Username { get; set; }
        public string Password { get; set; }
        public bool Successful { get; set; }
        public CredentialsFormHelper()
        {
            InitializeComponent();
        }

        public bool GetCredentials(string serverName, IntPtr hwndParent, out NetworkCredential? networkCredential)
        {
            bool save = false;
            int errorcode = 0;
            uint dialogReturn;
            uint authPackage = 0;
            IntPtr outCredBuffer = new IntPtr();
            uint outCredSize;

            CredentialsPromptHelper.CREDUI_INFO credui = new();
            credui.cbSize = Marshal.SizeOf(credui);
            credui.pszCaptionText = "Login";
            credui.pszMessageText = "Bitte geben Sie ihre Logindaten ein!";
            credui.hwndParent = hwndParent;

            dialogReturn = CredentialsPromptHelper.CredUIPromptForWindowsCredentials(ref credui, errorcode, ref authPackage, IntPtr.Zero, 0, out outCredBuffer, out outCredSize, ref save, CredentialsPromptHelper.PromptForWindowsCredentialsFlags.CREDUIWIN_GENERIC);

            var usernameBuf = new StringBuilder(100);
            var passwordBuf = new StringBuilder(100);
            var domainBuf = new StringBuilder(100);

            int maxUserName = 100;
            int maxDomain = 100;
            int maxPassword = 100;

            if (dialogReturn == 0)
            {
                if (CredentialsPromptHelper.CredUnPackAuthenticationBuffer(0, outCredBuffer, outCredSize, usernameBuf, ref maxUserName, domainBuf, ref maxDomain, passwordBuf, ref maxPassword))
                {
                    CredentialsPromptHelper.CoTaskMemFree(outCredBuffer);
                    networkCredential = new NetworkCredential()
                    {
                        UserName = usernameBuf.ToString(),
                        Password = passwordBuf.ToString(),
                        Domain = domainBuf.ToString()
                    };
                    return true;
                }
            }
            networkCredential = null;
            return false;
        }

        public static string SecureStringToString(SecureString value)
        {
            IntPtr valuePtr = IntPtr.Zero;

            try
            {
                valuePtr = Marshal.SecureStringToGlobalAllocUnicode(value);
                string? unicodeString = Marshal.PtrToStringUni(valuePtr);
                byte[] bytes = Encoding.Unicode.GetBytes(unicodeString);
                bytes = Encoding.Convert(Encoding.Unicode, Encoding.UTF8, bytes);
                return Encoding.UTF8.GetString(bytes);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
                return String.Empty;
            }
            finally { Marshal.ZeroFreeGlobalAllocUnicode(valuePtr); }
        }

        private void CredentialsFormHelper_Load(object sender, EventArgs e)
        {
            this.Visible = false;

            if (GetCredentials("", this.Handle, out NetworkCredential? networkCredential))
            {
                this.Username = networkCredential.UserName;
                this.Password = SecureStringToString(networkCredential.SecurePassword);
                this.Successful = true;
            }
            else
                this.Successful = false;

            this.Close();
        }
    }