How can I set me UWP page to have a constant width and height at startup?

Question

I am creating a UWP app using C++ and XAML. How can I set the app's width and height to be constant?

I am completely new to XAML and I want to create a UWP app using C++/WinRT. I have set the page's width to 500 and the height to 200 but if I resize the page during runtime, and then I restart the app, the size of the page will still be the resized size. For example if I resize the page's width and height too 1000 during runtime (using my cursor to drag the page), when I then restart the app, the page's width and height will still be 1000.

Here is my main.cpp:

#include "pch.h"

using namespace winrt;

using namespace Windows::ApplicationModel;
using namespace Windows::ApplicationModel::Activation;
using namespace Windows::Foundation;
using namespace Windows::Storage;
using namespace Windows::UI::Xaml;
using namespace Windows::UI::Xaml::Controls;
using namespace Windows::UI::Xaml::Markup;

struct App : ApplicationT<App> {
    fire_and_forget OnLaunched(const LaunchActivatedEventArgs&) {
        const auto packageFolder = Package::Current().InstalledLocation();
        const auto file = co_await packageFolder.GetFileAsync(L"MainPage.xaml");
        const auto xaml = co_await FileIO::ReadTextAsync(file);

        const auto body = XamlReader::Load(xaml).as<Page>();

        auto window = Window::Current();
        window.Content(body);
        window.Activate();
    }
};

int __stdcall wWinMain(HINSTANCE, HINSTANCE, PWSTR, int) {
    Application::Start([](auto&&) {make<App>(); });
}

And here is my MainPage.xaml:

<Page
 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
 xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
 xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
 mc:Ignorable="d"
 Background="{ThemeResource ApplicationPageBackgroundThemeBrush}" 
 Width="500" Height="200">

<Grid HorizontalAlignment="Stretch" Margin="0,0,408,0" 
VerticalAlignment="Stretch"/>
</Page>

I would want the app to restore its size each time a start the app. So the width should always be 500 and the height should always be 200 on startup. I have no idea why this happens since I am completely new to this so any help would be appreciated.

Thanks.

Additionally I would want a fixed size of the page during runtime, meaning that the page will not be able to resize during runtime.

Xie Steven Xie Steven · Accepted Answer · 2019-01-17T06:12:50

UWP apps do not only run on desktop, it also run on tablet, phone etc. So, what you want to set a fixed size page was not realistic. But you could call the ApplicationView.TryResizeView(Size) Method to change the size of the view.

If you still want a fixed size of the page during runtime, you could handle the page's SizeChanged event, in its event handler, you could call ApplicationView.TryResizeView method to resize it to the original size.

How can I set me UWP page to have a constant width and height at startup?

1 Answers