延迟加载

延迟加载

当引用了其他具有页面的程序集时，默认会在进入页面的时候，加载对应的程序集。

假如程序集过大或者过多，首次加载会很慢，影响用户体验

微软提供了延迟加载的实现，配置如下：

1、首先你的项目要引用这个程序集

2、在Program.cs 注入后面用到的LazyAssemblyLoader

 builder.Services.AddScoped<LazyAssemblyLoader>();

3、将程序集在项目文件中指定为延迟加载项目

<ItemGroup>
	<BlazorWebAssemblyLazyLoad Include="Test-Blazor-Lib.dll" />
</ItemGroup>

4、在App.razor中指定Router的OnNavigateAsync

@using System.Reflection;
@using Microsoft.Extensions.Logging
@using Microsoft.AspNetCore.Components.WebAssembly.Services
@inject LazyAssemblyLoader AssemblyLoader
@inject ILogger<App> Logger

<Router AppAssembly="@typeof(Program).Assembly"
        AdditionalAssemblies="@lazyLoadedAssemblies"
        OnNavigateAsync="@OnNavigateAsync">
    <Found Context="routeData">
        <RouteView RouteData="@routeData" DefaultLayout="@typeof(BasicLayout)" />
    </Found>
    <NotFound>
        <LayoutView Layout="@typeof(BasicLayout)">
            <p>Sorry, there's nothing at this address.</p>
        </LayoutView>
    </NotFound>
</Router>
<AntContainer />

@code{  private List<Assembly> lazyLoadedAssemblies = new List<Assembly>();
    private async Task OnNavigateAsync(NavigationContext args)
    {
        try
        {
            Console.WriteLine($"Path: {args.Path}");
            if (args.Path == "test/index")
            {
                var assemblies = await AssemblyLoader.LoadAssembliesAsync(
                        new[] { "Test-Blazor-Lib.dll" });
                lazyLoadedAssemblies.AddRange(assemblies);
            }
        }
        catch (Exception ex)
        {
            Logger.LogError("Error: {Message}", ex.Message);
        }
    }}