Azure Function v4 .NET6本地加载Microsoft.Extensions.Http 7+失败

问题场景 #

本地运行Azure Functions v4 .NET6项目，通过Microsoft.Extensions.Http注册HttpClient，代码及配置如下：

Startup代码 #

using DinersService.Helpers;
using DinersService.Interfaces;
using Microsoft.Azure.Functions.Extensions.DependencyInjection;
using Microsoft.Extensions.DependencyInjection;

[assembly: FunctionsStartup(typeof(DinersService.Startup))]
namespace DinersService
{
    public class Startup : FunctionsStartup
    {
        public override void Configure(IFunctionsHostBuilder builder)
        {
            builder.Services.AddHttpClient();
            builder.Services.AddScoped<IApiClient, ApiClient>();
        }
    }
}

.csproj配置 #

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net6.0</TargetFramework>
    <AzureFunctionsVersion>v4</AzureFunctionsVersion>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Microsoft.Azure.Functions.Extensions" Version="1.1.0" />
    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="8.0.0" />
    <PackageReference Include="Microsoft.Extensions.Http" Version="8.0.0" />
    <PackageReference Include="Microsoft.NET.Sdk.Functions" Version="4.2.0" />
  </ItemGroup>
  <ItemGroup>
    <None Update="host.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </None>
    <None Update="local.settings.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
      <CopyToPublishDirectory>Never</CopyToPublishDirectory>
    </None>
  </ItemGroup>
</Project>

使用Microsoft.Extensions.Http 6.0.0版本时运行正常，但升级到7.0.0及以上版本时，出现以下错误：

Error configuring services in an external startup class. DinersService: Could not load file or assembly 'Microsoft.Extensions.Http, Version=8.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60'. The system cannot find the file specified. [2023-12-13T10:19:39.349Z] A host error has occurred during startup operation '628e8d49-0172-4230-a0e3-861455a94086'. [2023-12-13T10:19:39.350Z] Microsoft.Azure.WebJobs.Script: Error configuring services in an external startup class. DinersService: Could not load file or assembly 'Microsoft.Extensions.Http, Version=8.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60'. The system cannot find the file specified. Value cannot be null. (Parameter 'provider')

解决方法 #

• 对齐依赖包版本到.NET6兼容范围
  Azure Functions v4（基于.NET6）运行时依赖.NET6生态的Microsoft.Extensions系列组件，7.0+、8.0+版本的Microsoft.Extensions.Http和Microsoft.Extensions.DependencyInjection属于.NET7/.NET8版本，与.NET6运行时存在程序集版本冲突。需将这些包降级到.NET6的稳定版本，推荐使用6.0.16（.NET6的最新补丁版本）。

• 更新Microsoft.NET.Sdk.Functions到兼容版本
  当前使用的Microsoft.NET.Sdk.Functions 4.2.0版本较旧，建议升级到与.NET6匹配的最新4.x稳定版本（如4.2.1或更高），确保运行时与依赖包的兼容性。

• 清理编译缓存并重新生成

1. 删除项目目录下的bin和obj文件夹，彻底清除旧编译产物
2. 执行dotnet restore命令重新还原所有依赖
3. 重新编译并启动项目

• 添加程序集绑定重定向（可选）
  如果上述步骤仍无法解决版本冲突，可在项目根目录创建app.config文件，添加绑定重定向强制运行时使用兼容的版本：

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="Microsoft.Extensions.Http" publicKeyToken="adb9793829ddae60" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-6.0.0.0" newVersion="6.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="Microsoft.Extensions.DependencyInjection" publicKeyToken="adb9793829ddae60" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-6.0.0.0" newVersion="6.0.0.0" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
</configuration>

内容的提问来源于stack exchange，提问作者Mikkel Rohde Glerup