maui-performance

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.NET MAUI Performance Optimization

.NET MAUI 性能优化

Profiling

性能分析

dotnet-trace: Cross-platform profiler for all MAUI targets. Collect traces with:

shell

dotnet-trace collect --process-id <PID> --providers Microsoft-DotNETCore-SampleProfiler

PerfView (Windows only): Use for deep allocation and CPU analysis on WinUI targets.
Profile before optimizing — measure, don't guess.

dotnet-trace：适用于所有MAUI目标平台的跨平台性能分析器。使用以下命令收集跟踪数据：
shell
```
dotnet-trace collect --process-id <PID> --providers Microsoft-DotNETCore-SampleProfiler
```
PerfView（仅Windows）：用于WinUI目标平台的深度内存分配和CPU分析。
优化前先做性能分析——用数据说话，不要凭猜测。

Compiled Bindings

编译绑定

Always set
```
x:DataType
```
on pages/views to enable compiled bindings.
Compiled bindings are 8–20× faster than reflection-based bindings.
Required for NativeAOT and full trimming — reflection bindings break under trimming.
Apply
```
x:DataType
```
at the highest reasonable scope (page or root element).

xml

<ContentPage xmlns:vm="clr-namespace:MyApp.ViewModels"
             x:DataType="vm:MainViewModel">
    <Label Text="{Binding Title}" />
</ContentPage>

For

DataTemplate

inside

CollectionView

ListView

, set

x:DataType

on the template root:

xml

<DataTemplate x:DataType="model:Item">
    <Label Text="{Binding Name}" />
</DataTemplate>

Minimize unnecessary bindings: Static content that never changes doesn't need
```
{Binding}
```
. Use literal values or
```
x:Static
```
instead.

始终在页面/视图上设置
```
x:DataType
```
以启用编译绑定。
编译绑定的速度比基于反射的绑定快8-20倍。
这是NativeAOT和完全代码裁剪的必要条件——基于反射的绑定在裁剪后会失效。
在尽可能高的作用域（页面或根元素）上应用
```
x:DataType
```
。

xml

<ContentPage xmlns:vm="clr-namespace:MyApp.ViewModels"
             x:DataType="vm:MainViewModel">
    <Label Text="{Binding Title}" />
</ContentPage>

对于
```
CollectionView
```
/
```
ListView
```
中的
```
DataTemplate
```
，在模板根元素上设置
```
x:DataType
```
：

xml

<DataTemplate x:DataType="model:Item">
    <Label Text="{Binding Name}" />
</DataTemplate>

减少不必要的绑定：永远不会变化的静态内容不需要使用
```
{Binding}
```
，改用字面量值或
```
x:Static
```
。

Layout Optimization

布局优化

Avoid nested single-child layouts — a
```
StackLayout
```
with one child is pointless overhead.
Prefer
Grid
over nested
StackLayout
/
VerticalStackLayout
— Grid resolves layout in a single pass.
Use
```
IsVisible="False"
```
to hide elements rather than adding/removing from the tree at runtime.
Remove unnecessary wrapper containers — every layout adds a measure/arrange pass.
Avoid
AbsoluteLayout
when
```
Grid
```
with row/column definitions achieves the same result.
Set explicit
```
WidthRequest
```
/
```
HeightRequest
```
where sizes are known to reduce measure passes.

避免嵌套单元素布局——仅包含一个子元素的
```
StackLayout
```
会造成无意义的性能开销。
优先使用
Grid
而非嵌套的
StackLayout
/
VerticalStackLayout
——Grid只需一次遍历即可完成布局计算。
使用
```
IsVisible="False"
```
隐藏元素，而非在运行时从布局树中添加/移除元素。
移除不必要的包装容器——每个布局都会增加一次测量/排列的开销。
当使用带行列定义的
```
Grid
```
可以实现相同效果时，避免使用
AbsoluteLayout
。
在已知尺寸的元素上设置明确的
```
WidthRequest
```
/
```
HeightRequest
```
，以减少测量次数。

CollectionView and ListView

CollectionView 与 ListView

Use
```
ItemSizingStrategy="MeasureFirstItem"
```
on
```
CollectionView
```
when items have uniform height — avoids measuring every item individually.

xml

<CollectionView ItemSizingStrategy="MeasureFirstItem"
                ItemsSource="{Binding Items}">

Prefer
```
CollectionView
```
over
```
ListView
```
for new development.
Keep
```
DataTemplate
```
visual trees shallow — fewer nested layouts per item.

当
```
CollectionView
```
中的项具有统一高度时，设置
```
ItemSizingStrategy="MeasureFirstItem"
```
——避免逐个测量每个项。

xml

<CollectionView ItemSizingStrategy="MeasureFirstItem"
                ItemsSource="{Binding Items}">

新开发优先使用
```
CollectionView
```
而非
```
ListView
```
。
保持
```
DataTemplate
```
的视觉树层级简洁——每个项的嵌套布局越少越好。

Image Optimization

图片优化

Size images to display resolution — don't load a 4000×3000 image for a 200×200 display.
Use
```
Aspect="AspectFill"
```
or
```
AspectFit
```
and set explicit dimensions.

Cache downloaded images:

CachingEnabled="True"

(default) on

UriImageSource

, set

CacheValidity

Use platform-appropriate formats (WebP for Android, HEIF/PNG for iOS).
For icons and simple graphics, prefer SVG or vector-based font icons.

根据显示分辨率调整图片尺寸——不要为200×200的显示区域加载4000×3000的图片。
使用
```
Aspect="AspectFill"
```
或
```
AspectFit
```
并设置明确的尺寸。
缓存下载的图片：
```
UriImageSource
```
默认启用
```
CachingEnabled="True"
```
，可设置
```
CacheValidity
```
。
使用平台适配的格式（Android用WebP，iOS用HEIF/PNG）。
对于图标和简单图形，优先使用SVG或基于矢量的字体图标。

Resource Dictionaries

资源字典

App-level (
```
App.xaml
```
): Shared styles, colors, converters used across multiple pages.
Page-level: Styles/resources specific to a single page — keeps App.xaml lean.
Avoid duplicating resources across dictionaries.
Use
```
MergedDictionaries
```
to organize large resource sets without bloating a single file.

应用级（
```
App.xaml
```
）：存放多页面共享的样式、颜色、转换器。
页面级：存放仅单个页面使用的样式/资源——保持App.xaml简洁。
避免在多个字典中重复定义资源。
使用
```
MergedDictionaries
```
组织大型资源集合，避免单个文件过于臃肿。

Startup Optimization

启动优化

Minimize work in
```
App
```
constructor and
```
MainPage
```
constructor.
Defer non-essential service registration — use lazy initialization where possible.
Reduce the number of XAML pages parsed at startup (use
```
Shell
```
routing for deferred loading).
Remove unused
```
Handlers
```
/
```
Effects
```
registrations from
```
MauiProgram.cs
```
.
On Android, ensure
```
AndroidManifest.xml
```
doesn't force unnecessary permissions checks at launch.

减少
```
App
```
构造函数和
```
MainPage
```
构造函数中的操作。
延迟非必要的服务注册——尽可能使用延迟初始化。
减少启动时解析的XAML页面数量（使用
```
Shell
```
路由实现延迟加载）。
从
```
MauiProgram.cs
```
中移除未使用的
```
Handlers
```
/
```
Effects
```
注册。
在Android上，确保
```
AndroidManifest.xml
```
不会在启动时强制进行不必要的权限检查。

Trimming

代码裁剪

Enable IL trimming to reduce app size and remove unused code:

xml

<PropertyGroup>
    <PublishTrimmed>true</PublishTrimmed>
    <TrimMode>full</TrimMode>
</PropertyGroup>

Test thoroughly — trimming can remove code accessed only via reflection.

Use

[DynamicDependency]

[UnconditionalSuppressMessage]

to preserve reflection targets.

Compiled bindings are essential — reflection-based bindings will be trimmed away.

启用IL裁剪以减小应用体积并移除未使用的代码：

xml

<PropertyGroup>
    <PublishTrimmed>true</PublishTrimmed>
    <TrimMode>full</TrimMode>
</PropertyGroup>

彻底测试——裁剪可能会移除仅通过反射访问的代码。

使用

[DynamicDependency]

或

[UnconditionalSuppressMessage]

保留反射目标。

编译绑定是必要条件——基于反射的绑定会被裁剪掉。

NativeAOT

NativeAOT compiles to native code ahead-of-time for faster startup and smaller footprint.
Requirements: compiled bindings, no unconstrained reflection, trimming-compatible code.

xml

<PropertyGroup>
    <PublishAot>true</PublishAot>
    <PublishTrimmed>true</PublishTrimmed>
</PropertyGroup>

Audit third-party NuGet packages for trimming/AOT compatibility.
Use
```
[JsonSerializable]
```
source generators instead of reflection-based JSON serialization.
Run
```
dotnet publish
```
with AOT to verify no warnings before shipping.

NativeAOT提前编译为原生代码，实现更快的启动速度和更小的内存占用。
要求：使用编译绑定、无无约束反射、代码兼容裁剪。

xml

<PropertyGroup>
    <PublishAot>true</PublishAot>
    <PublishTrimmed>true</PublishTrimmed>
</PropertyGroup>

检查第三方NuGet包是否兼容裁剪/AOT。
使用
```
[JsonSerializable]
```
源生成器替代基于反射的JSON序列化。
发布前使用
```
dotnet publish
```
命令结合AOT进行验证，确保无警告。

Quick Checklist

快速检查清单

✅
```
x:DataType
```
on all pages, templates, and data-bound views
✅ No nested single-child layouts
✅ Grid preferred over nested StackLayouts
✅ Images sized to display, caching enabled
✅
```
ItemSizingStrategy="MeasureFirstItem"
```
on uniform CollectionViews
✅ Startup work minimized and deferred
✅ Trimming enabled and tested
✅ Profile with dotnet-trace before and after changes

✅ 所有页面、模板和数据绑定视图都已设置
```
x:DataType
```
✅ 无嵌套单元素布局
✅ 优先使用Grid而非嵌套StackLayout
✅ 图片已按显示尺寸调整，缓存已启用
✅ 统一高度的CollectionView已设置
```
ItemSizingStrategy="MeasureFirstItem"
```
✅ 启动时的操作已最小化并延迟执行
✅ 已启用代码裁剪并完成测试
✅ 优化前后均使用dotnet-trace进行性能分析