Question

我正在创建一个自定义的visual studio扩展。在其初始化代码中，我使用async-await将异步WebRequest发送到远程端点。

问题是，当我调用await语句时，我的自定义扩展初始化的执行停止并且永远不会返回它。我怀疑VS扩展初始化代码在异步编程方面有些特殊。如果有人能指出我为什么会这样做的解释，我会非常感激。

Answer 1

有一个名为AsyncPackage的新程序包允许异步加载程序包。它有一个AsyncInitialize。摘自MSDN：

您需要添加对Microsoft.VisualStudio.Shell.Interop.14.0.DesignTime的引用才能使其正常工作

using System;
using System.Runtime.InteropServices;
using Microsoft.VisualStudio;
using Microsoft.VisualStudio.Shell;
using System.Threading;
using System.Runtime.CompilerServices;
using System.IO;

namespace asyncpackagetest
{
    [ProvideService((typeof(STextWriterService)), IsAsyncQueryable = true)]
    [ProvideAutoLoad(VSConstants.UICONTEXT.NoSolution_string, PackageAutoLoadFlags.BackgroundLoad)]
    [PackageRegistration(UseManagedResourcesOnly = true, AllowsBackgroundLoading = true)]
    [Guid(VSPackage1.PackageGuidString)]
    public sealed class VSPackage1 : AsyncPackage
    {

        public const string PackageGuidString = "3dc186f8-2146-4d89-ac33-e216b3ead526";

        public VSPackage1()
        {

        }

        protected override async System.Threading.Tasks.Task InitializeAsync(CancellationToken cancellationToken, IProgress<ServiceProgressData> progress)
        {
            this.AddService(typeof(STextWriterService), CreateService);
            await base.InitializeAsync(cancellationToken, progress);
            ITextWriterService textService = await this.GetServiceAsync(typeof(STextWriterService)) as ITextWriterService;
            await textService.WriteLineAsync(@"c:\windows\temp\async_service.txt", "this is a test");

        }

        public async System.Threading.Tasks.Task<object> CreateService(IAsyncServiceContainer container, CancellationToken cancellationToken, Type serviceType)
        {
            STextWriterService service = null;
            await System.Threading.Tasks.Task.Run(() => {
                service = new TextWriterService(this);
            });

            return service;
        }

        public class TextWriterService : STextWriterService, ITextWriterService
        {
            private Microsoft.VisualStudio.Shell.IAsyncServiceProvider serviceProvider;
            public TextWriterService(Microsoft.VisualStudio.Shell.IAsyncServiceProvider provider)
            {
                serviceProvider = provider;
            }
            public async System.Threading.Tasks.Task WriteLineAsync(string path, string line)
            {
                StreamWriter writer = new StreamWriter(path);
                await writer.WriteLineAsync(line);
                writer.Close();
            }
            public TaskAwaiter GetAwaiter()
            {
                return new TaskAwaiter();
            }
        }
        public interface STextWriterService
        {
        }
        public interface ITextWriterService
        {
            System.Threading.Tasks.Task WriteLineAsync(string path, string line);
            TaskAwaiter GetAwaiter();
        }
    }
}

Visual Studio扩展包是否支持异步操作

1 个答案: