Public Function GetCredentials() As  _
    ClientFormsAuthenticationCredentials Implements _
    IClientFormsAuthenticationCredentialsProvider.GetCredentials

    If Me.ShowDialog() = DialogResult.OK Then
        Return New ClientFormsAuthenticationCredentials( _
            UsernameTextBox.Text, PasswordTextBox.Text, _
            rememberMeCheckBox.Checked)
    Else
        Return Nothing
    End If

End Function

public ClientFormsAuthenticationCredentials GetCredentials()
{
    if (this.ShowDialog() == DialogResult.OK)
    {
        return new ClientFormsAuthenticationCredentials(
            usernameTextBox.Text, passwordTextBox.Text,
            rememberMeCheckBox.Checked);
    }
    else
    {
        return null;
    }
}