Fix memory leaks

[watfordjc]

Feature Branch

Current feature branch for this issue: not created yet.

Progress

• Find all the memory leaks and make them disappear.
  • Potential memory leak on disconnect/timer/reconnect.
  • Memory leak on system theme changes.

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Background

Memory leaks are bad, especially ones that double the number of objects and heap size.

Find the C#/WPF/CLR equivalent of gdb and work out how to use it. Then use the information to work out the cause.

[watfordjc]

Cause of Bug

The problem appears to be with the system tray ContextMenu and its MenuItems and its/their styles.

The reason the SystemTrayIcon instance is restarted is because I can't find a way to use dynamic styles in its menus. The reason memory usage increases on Windows theme change is because the styles aren't released when the instance is replaced.

This whole process is a kludge as WPF .NET Core doesn't know squat about light/dark mode settings in Windows 10, although I believe even UWF apps can only use themes for "app mode" dark/light mode and the system tray context menu should be using themes for "Windows mode" dark/light mode.

Option 1: Ignore Bug

On the one hand, this bug could be ignored. Microsoft say Windows theme changes should be applied without requiring the restart of an application but they haven't even bothered to create colours/brushes/themes for Aero2 light/dark modes — the window background colour for a program, according to Microsoft Windows, is pure white when "app mode" is set to dark mode.

The program currently eats an extra ~0.5 mebibytes of RAM whenever someone changes their Windows theme preferences until the application is restarted. Wasteful, yes, but how often do people change that setting unless they are programming and/or doing accessibility work?

WinUI 3.0 might offer something, but that is some way off from release.

Option 2: Waste Time Rewriting Code

Learning WPF, .NET Core 3.0, Win32, COM, C#, and everything else that has so far gone into this repository has been a gradual process.

There is inelegant code. There is poor quality code. There are zero tests.

Then there are things that are only there because either WPF is badly designed or I haven't found the correct way of doing something.

Use DynamicResource? That doesn't work.
Use "skinning"? That doesn't work.
Replace every brush colour value? That doesn't work.
Replace resource dictionaries? That doesn't work.
Use WeakReference? That doesn't work.
Walk through all the resources so they can later be garbage collected? That doesn't work.

I have just spent 3 days trying to get skinning to work, and all I ended up with was a context menu that was completely ignoring all of the styles it should've been using. I could either have it use Windows default colours, or I could have it display nothing but its drop shadow.

The reason rewriting the code would be a waste of time is because I have probably spent over 168 hours so far trying to fix this bug. I could be looking at Twitter or Twitch APIs, but instead I am trying to stop half a meg of RAM being held on to if a user does something they probably shouldn't be doing when streaming anyway.

Option 3: Research

I have already spent over a week researching the whole theming/skinning issue and the only reason the tray context menu works is because the current code is the only code that has worked.

Light Theme

<ResourceDictionary.MergedDictionaries>
    <ResourceDictionary Source="LightColours.xaml" />
    <ResourceDictionary Source="..\Templates\TextBoxTemplate.xaml" />
    <ResourceDictionary Source="..\Templates\ContextMenuTemplate.xaml" />
    <ResourceDictionary Source="..\Templates\MenuItemTemplate.xaml" />
</ResourceDictionary.MergedDictionaries>

<Style x:Key="ContextMenuStyle" TargetType="{x:Type ContextMenu}" BasedOn="{StaticResource ResourceKey=StyledContextMenu}">
    <Style.Resources>
        <ResourceDictionary Source="LightColours.xaml" />
    </Style.Resources>
</Style>

If I don't include LightColours.xaml in the resources for ContextMenuStyle, it ignores the colours. If I don't include ContextMenuTemplate in MergedDictionaries, then StyledContextMenu cannot be found.

The whole dictionary traversal to look for missing things simply doesn't happen.

Decision

For now, I am going with option 1: ignore the bug.

It isn't my preferred option, but I have wasted too much time on something I don't know how to fix or even if it can be fixed.

I'll take another look after WinUI 3.0 and .NET 5.0 are released.