C# Microsoft.AspNet.TestHost异常：找不到方法AddInstance_C#_Asp.net_Asp.net Mvc_Integration Testing_Asp.net Core

C# Microsoft.AspNet.TestHost异常：找不到方法AddInstance

c# asp.net asp.net-mvc asp.net-core

C# Microsoft.AspNet.TestHost异常：找不到方法AddInstance,c#,asp.net,asp.net-mvc,integration-testing,asp.net-core,C#,Asp.net,Asp.net Mvc,Integration Testing,Asp.net Core,我正在尝试使用Microsoft.AspNet.TestHost（它使用Microsoft.AspNet.Hosting包）进行集成测试，但出现以下错误：找不到方法： 'Microsoft.Extensions.DependencyInjection.IServiceCollection Microsoft.Extensions.DependencyInjection.ServiceCollectionExtensions.AddInstance（Microsoft.Extensions.De

我正在尝试使用Microsoft.AspNet.TestHost（它使用Microsoft.AspNet.Hosting包）进行集成测试，但出现以下错误：

找不到方法： 'Microsoft.Extensions.DependencyInjection.IServiceCollection Microsoft.Extensions.DependencyInjection.ServiceCollectionExtensions.AddInstance（Microsoft.Extensions.DependencyInjection.IServiceCollection，！！0）

在“调试”下加载Microsoft.Extensions.DependencyInjection\1.0.0-rc2-15877，这是旧版本。我不确定我做错了什么：

var  _server = new TestServer(TestServer.CreateBuilder().UseStartup< Foo.FrontEnd.Startup>());

"Microsoft.AspNet.TestHost": "1.0.0-rc1-final",
"Microsoft.AspNet.Http.Abstractions": "1.0.0-rc1-final",