Roslyn CompletionService 不返回静态扩展方法答案

【问题标题】：Static Extension Methods are not returned by the Roslyn CompletionServiceRoslyn CompletionService 不返回静态扩展方法
【发布时间】：2020-01-17 17:07:42
【问题描述】：

如果'使用 System.Linq;'存在并且 System.Linq 是引用的程序集之一，我希望 int[] 数组上的 Completions 返回 LINQ 扩展方法，例如Select(...), Where(...) 等。事实上，我只获取 int[] 类型的公共方法和属性。完整代码如下：

static void Main(string[] args)
    {
        string code = @"using System;
        using System.Linq;

       namespace RoslynCompletionTests
       {
             public static class MyTestClass1
             {
                   public static void Print()
                   {
                          int[] array = {1,2,3,4,5,6};

                          var result = array.Select(i => new { I = i }).Select(v => v.I);
                   }
             }
       }";
        var host = MefHostServices.Create(MefHostServices.DefaultAssemblies);

        Type[] types =
        {
            typeof(object),
            typeof(Enumerable),
            typeof(IEnumerable),
            typeof(Console),
            typeof(Assembly),
            typeof(List<>),
            typeof(Type)
        };

        ImmutableArray<string> imports = types.Select(x => x.Namespace).Distinct().ToImmutableArray();

        ImmutableArray<MetadataReference> references =
            types.Select(t => MetadataReference.CreateFromFile(t.Assembly.Location) as MetadataReference)
                 .ToImmutableArray();

        AdhocWorkspace workspace = new AdhocWorkspace(host, "Custom");

        string name = "MyTestProj";

        ProjectId id = ProjectId.CreateNewId(name);

        ParseOptions parseOptions = new CSharpParseOptions();

        CompilationOptions compilationOptions =
            new CSharpCompilationOptions
            (
                OutputKind.DynamicallyLinkedLibrary,
                usings: imports,
                allowUnsafe: true);

        ProjectInfo projInfo =
            ProjectInfo.Create
            (
                id,
                VersionStamp.Create(),
                name,
                name,
                LanguageNames.CSharp,
                parseOptions: parseOptions,
                compilationOptions: compilationOptions,
                metadataReferences: references);

        Project proj = workspace.AddProject(projInfo);

        SourceText text = SourceText.From(code);

        Document doc = proj.AddDocument("MyDoc.cs", text);

        SemanticModel semanticModel = doc.GetSemanticModelAsync().Result;

        CompletionService completionService = CompletionService.GetService(doc);

        string strToFind = "array.";
        int idx = text.ToString().IndexOf(strToFind) + strToFind.Length;

        var results = completionService.GetCompletionsAsync(doc, idx).Result;
    }

我做错了吗？

【问题讨论】：

标签： c# roslyn

【解决方案1】：

事实证明，我必须添加对构成 MetadataReferences 的某些程序集的引用：

var assemblies = types.Select(t => t.Assembly).Concat(new[]
        {
            Assembly.Load("System.Runtime, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"),
            typeof(Microsoft.CSharp.RuntimeBinder.Binder).Assembly,
        });

之后一切都开始工作了。

【讨论】：