C# Maui Secondary window/contentpage opens the same size as MainPage

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Summary

The issue at hand is that a secondary window in a C# Maui application is opening with the same size as the MainPage, despite being set to a specific size in XAML. This is causing the window to be resizable and not fixed to the desired dimensions.

Root Cause

The root cause of this issue is due to the following reasons:

  • The Window class in Maui does not respect the size requests set in the XAML of the ContentPage.
  • The OpenWindow method of the App class is used to open the new window, which does not provide an option to set the window size.
  • The MinimumWidthRequest and MaximumWidthRequest properties, as well as the MinimumHeightRequest and MaximumHeightRequest properties, are only respected within the context of the ContentPage itself, not the window that contains it.

Why This Happens in Real Systems

This issue can occur in real systems when:

  • Developers assume that the size requests set in XAML will be respected by the window that contains the page.
  • The window size is not explicitly set when opening the new window.
  • The ContentPage is used as a standalone window, rather than being embedded within a larger application.

Real-World Impact

The impact of this issue can be:

  • Unintended user experience: The window may be larger or smaller than expected, which can affect the layout and usability of the application.
  • Security risks: If the window is resizable, it may be possible for an attacker to manipulate the window size to access sensitive information or exploit vulnerabilities.
  • Performance issues: If the window is larger than expected, it may consume more system resources than necessary, leading to performance issues.

Example or Code

private async void OnClickEvent(object sender, EventArgs e)
{
    var infoDisplay = new InfoDisplay();
    var loadedWindow = new Window(infoDisplay);
    // Set the window size explicitly
    loadedWindow.Width = 800;
    loadedWindow.Height = 600;
    loadedWindow.Resizable = false;
    App.Current?.OpenWindow(loadedWindow);
}

How Senior Engineers Fix It

Senior engineers can fix this issue by:

  • Explicitly setting the window size when opening the new window.
  • Using the Window class properties to set the window size and resizability.
  • Verifying the window size after it has been opened to ensure it matches the expected dimensions.

Why Juniors Miss It

Junior engineers may miss this issue because:

  • They may not be aware of the difference between ContentPage size requests and window size.
  • They may not explicitly set the window size when opening the new window.
  • They may not test the window size after it has been opened to ensure it matches the expected dimensions.

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