We recommend reviewing our guide

on writing a quality question to help you clearly summarize your issue and provide the details needed for helpful answers.

if (auto clientPresenter = m_clientAreaPresenter.as<xaml::IFrameworkElement>();
	clientPresenter)
{
	winrt::check_hresult(clientPresenter->put_Height(static_cast<int32_t>(m_targetContentRect.Height)));
	winrt::check_hresult(clientPresenter->put_Width(static_cast<int32_t>(m_targetContentRect.Width)));
}