如何进一步优化Windows Store应用程序？

Question

I have 2 levels deep collection that I render into something like a Header, Child Item.

Roughly, my code looks something like this:

    <ScrollViewer>
        <ItemsControl IsEnabled="{Binding Path=IsEnabled}"
                      ItemsSource="{Binding Path=HeaderViewModels, Mode=OneTime}">
            <ItemsControl.ItemsPanel>
                <ItemsPanelTemplate>
                    <StackPanel Orientation="Horizontal" />
                </ItemsPanelTemplate>
            </ItemsControl.ItemsPanel>
            <ItemsControl.ItemsTemplate>
                <DataTemplate>
                    <StackPanel Visibility="{Binding Path=ShouldShow, Converter={StaticResource SomeConverter}}">
                        <TextBlock Text="{Binding Path=Description, Mode=OneTime}" />
                        <ItemsControl ItemsPanel="{StaticResource WinRTXAMLWrapPanel}"
                                      ItemsSource="{Binding Path=ChildViewModels, Mode=OneTime}">
                            <i:Interaction.Behaviors>
                                <SomeClass:AdjustSizeBehavior SizeFromParentMode="Height" />
                            </i:Interaction.Behaviors>
                            <ItemsControl.ItemsTemplate>
                                <DataTemplate>
                                <ContentControl>
                                    <i:Interaction.Behaviors>
                                        <SomeClass:IsEnabledBehavior />
                                        <SomeClass:PointerPressBehavior />
                                        <SomeClass:PointerLeaveBehavior />
                                    </i:Interaction.Behaviors>
                                    <StackPanel>
                                        <TextBlock Text="X">
                                            <i:Interaction.Behaviors>
                                                <SomeClass:SetXMarkColor />
                                            </i:Interaction.Behaviors>
                                        </TextBlock>
                                        <TextBlock Text="{Binding Path=Description, Mode=OneTime}" />
                                    </StackPanel>
                                </ContentControl>
                                </DataTemplate>
                            </ItemsControl.ItemsTemplate>
                        </ItemsControl>
                    </StackPanel>
                </DataTemplate>
            </ItemsControl.ItemsTemplate>
        </ItemsControl>
    </ScrollViewer>

Left out the styling, but its pretty much background, margins, font-size, etc. Also, you can see I'm using lots of Bindings and Behaviors.

I already did most of the optimization I can think of. Removed unnecessary UI elements (ex. rectangles used for 'backgrounds'), used StackPanel instead of Grid, set column / height to static instead of auto. Basically done what I can on this links: Twelve ways to improve wpf performance and Best practices for Windows Store Apps

With the optimizations I have done, I have actually reduced loading time of 10 headers + 8 child each (total of 80), from 1.8 sec to around 0.5 ms - 0.6 ms.

However, I would like it to reach less than 0.5 ms so it is like 'instant'.

Is there anything else I can do to improve performance?

Thank you!

Answer 1

It looks like your XAML is quite clean. What about your C# code?

If you use async/await, and push tasks into a background thread, it can really boost performance. Async/await is the secret to creating fast, ressponsive apps.

Visual Studio 2015 has some great improvements when it comes to identifying and fixing WPF performance bottlenecks.

You can identify which lines of code are taking the longest, and are thus a candidate for pushing onto a background thread using async/await, using the profiler. The profiler is awesome: it displays how long each block or line of code has taken, in milliseconds, right in the editor.

More:

• https://channel9.msdn.com/Events/Build/2015/3-635
• https://channel9.msdn.com/Events/dotnetConf/2015/Debugging-Performance-Issues-Using-Visual-Studio-2015

While we are at it, if Microsoft implements compile time bindings in WPF, it will dramatically boost performance. Binding speed can be as much as 10x faster as its no longer based on reflection. Add your vote to implement this feature here: https://visualstudio.uservoice.com/forums/121579-visual-studio/suggestions/7810488-implement-x-bind-for-wpf

Answer 2

The question of whether or not to use to use a master/detail grid is an interesting related question. I was chatting to a dev who has been using WPF since it was released in 2006. He is a bit of a guru, and he was of the opinion that master/detail grids are not always the best thing from both a usability and speed point of view. The reason is that you almost always end up loading all of the details on startup, which is slow, unless you resort to some interesting tricks to lazy load in the background. And if you have a few of the detail grids expanded, the screen begins to look messy.

Its almost as if master/detail grids are possible, but they are not a generally a good idea. Look around for successful, usable software that uses master/detail grids. They are relatively rare on the evolutionary landscape, with the exception of Windows Explorer style interfaces. They are not very common in Apple land, which is a hint that they are perhaps not optimum from a users point of view.

And the really odd thing is that relatively experienced programmers tend to like master/detail grids - a lot. They seem to have an intuitive appeal to programmers because they model the data so well. But from a users point of view, they would rather have a flat grid that loads up quickly, and a Properties panel below the grid which always displays details of the current row we have selected.

Yes, this answer doesn't address your exact question - it's too philosophical for that - but it sure as hell would solve your speed problems in one neat refactor, and potentially make your app more intuitive for your users.