public Task<Credentials> GetUserCredentialsAsync(string authority, bool invalidateStoredCredentials, CancellationToken cancellationToken = default(CancellationToken)) {
_coreShell.AssertIsOnMainThread();
var showDialog = invalidateStoredCredentials;
var credentials = new Credentials();
var passwordStorage = IntPtr.Zero;
try {
var userNameBuilder = new StringBuilder(CREDUI_MAX_USERNAME_LENGTH + 1);
var save = false;
var flags = CREDUI_FLAGS_EXCLUDE_CERTIFICATES | CREDUI_FLAGS_PERSIST | CREDUI_FLAGS_EXPECT_CONFIRMATION | CREDUI_FLAGS_GENERIC_CREDENTIALS;
if(showDialog) {
flags |= CREDUI_FLAGS_ALWAYS_SHOW_UI;
}
var credui = new CREDUI_INFO {
cbSize = Marshal.SizeOf(typeof(CREDUI_INFO)),
hwndParent = _coreShell.AppConstants.ApplicationWindowHandle
};
// For password, use native memory so it can be securely freed.
passwordStorage = SecurityUtilities.CreatePasswordBuffer();
var err = CredUIPromptForCredentials(ref credui, authority, IntPtr.Zero, 0, userNameBuilder, userNameBuilder.Capacity, passwordStorage, CREDUI_MAX_PASSWORD_LENGTH, ref save, flags);
if (err != 0) {
throw new OperationCanceledException();
}
credentials.UserName = userNameBuilder.ToString();
credentials.Password = SecurityUtilities.SecureStringFromNativeBuffer(passwordStorage);
credentials.Password.MakeReadOnly();
} finally {
if (passwordStorage != IntPtr.Zero) {
Marshal.ZeroFreeGlobalAllocUnicode(passwordStorage);
}
}
return Task.FromResult(credentials);
}