c# – 使用Roslyn编译语法树

但是,由于某种原因,编译程序集失败,添加Linq名称空间时出错(错误CS0246：找不到类型或名称空间名称’System.Linq'(您是否缺少using指令或程序集引用？)}) .

我曾尝试以多种方式操作生成的树并编译每个,但仍然编译失败.

编译成功的唯一方法是将树解析为字符串,然后解析回语法树然后编译.

以下代码执行以下操作：

>构建一个包含编译单元,使用,命名空间,类和属性的简单语法树.
>尝试编译树(失败)
>使用C#6选项生成新的语法树并编译(失败)
>格式化语法树并编译(失败)
>将树序列化为字符串,然后使用SyntaxFactory.ParseSyntaxTree并编译生成的树(成功)

代码：

private static readonly CSharpCompilationOptions DefaultCompilationOptions =
        new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary)
                .WithOverflowChecks(true)
                .WithPlatform(Platform.X86)
                .WithOptimizationLevel(OptimizationLevel.Release)
                .WithUsings(DefaultNamespaces);
    private static readonly IEnumerable<string> DefaultNamespaces =
        new[]
        {
                    "System","System.IO","System.Net","System.Linq","System.Text","System.Text.RegularExpressions"
        };

    private static readonly IEnumerable<MetadataReference> DefaultReferences =
        new[]
        {
                    MetadataReference.CreateFromFile(typeof (object).Assembly.Location),MetadataReference.CreateFromFile(typeof (System.Linq.Enumerable).Assembly.Location),MetadataReference.CreateFromFile(typeof (System.GenericUriParser).Assembly.Location),MetadataReference.CreateFromFile(typeof (Microsoft.CSharp.RuntimeBinder.RuntimeBinderException).Assembly.Location)
        };

    static void Main(string[] args)
    {
        MakeAssembly();
        Console.ReadLine();
    }

    private static void MakeAssembly()
    {
        //Compilation Unit and Usings
        CompilationUnitSyntax cu = SyntaxFactory.CompilationUnit()
            .AddUsings(SyntaxFactory.UsingDirective(SyntaxFactory.IdentifierName("System")),SyntaxFactory.UsingDirective(SyntaxFactory.IdentifierName(typeof(System.Linq.Enumerable).Namespace)))
        ;

        // NameSpace
        NamespaceDeclarationSyntax ns = SyntaxFactory.NamespaceDeclaration(SyntaxFactory.IdentifierName("Roslyn"));

        // Class
        ClassDeclarationSyntax classNode = SyntaxFactory.ClassDeclaration("MyClass")
                        .AddModifiers(SyntaxFactory.Token(SyntaxKind.PublicKeyword))
                    ;

        // Property
        classNode= classNode.AddMembers(
                                SyntaxFactory.PropertyDeclaration(SyntaxFactory.ParseTypeName("Int32"),"MyProperty")
                                        .AddAccessorListAccessors(
                                        SyntaxFactory.AccessorDeclaration(SyntaxKind.GetAccessorDeclaration).WithSemicolonToken(SyntaxFactory.Token(SyntaxKind.SemicolonToken)),SyntaxFactory.AccessorDeclaration(SyntaxKind.SetAccessorDeclaration).WithSemicolonToken(SyntaxFactory.Token(SyntaxKind.SemicolonToken))).
                                        AddModifiers(SyntaxFactory.Token(SyntaxKind.PublicKeyword)));
        ns = ns.AddMembers(classNode);
        cu = cu.AddMembers(ns);

        // Try To Compile Syntax Tree root
        var root = cu.SyntaxTree.GetRoot();
        var st = root.SyntaxTree;
        var assembly = CompileAndLoad(st);

        if (assembly != null)
        {
            Console.WriteLine("Success compile syntax tree root");
            return;
        }
        else
            Console.WriteLine("failed to compile syntax tree root");

        // Try to compile new syntax tree
        var stNew = SyntaxFactory.SyntaxTree(cu,CSharpParSEOptions.Default.WithLanguageVersion(LanguageVersion.CSharp6));
        assembly = CompileAndLoad(stNew);
        if (assembly != null)
        {
            Console.WriteLine("Success compile new syntax tree");
            return;
        }
        else
            Console.WriteLine("failed to compile new syntax tree");

        // Try to format node
        AdhocWorkspace cw = new AdhocWorkspace();
        OptionSet options = cw.Options;
        options = options.WithChangedOption(CSharpFormattingOptions.NewLinesForBracesInMethods,false);
        options = options.WithChangedOption(CSharpFormattingOptions.NewLinesForBracesInTypes,false);

        SyntaxNode formattedNode = Formatter.Format(cu,cw,options);
        var stFormat = SyntaxFactory.SyntaxTree(cu,CSharpParSEOptions.Default.WithLanguageVersion(LanguageVersion.CSharp6));
        assembly = CompileAndLoad(stFormat);
        if (assembly != null)
        {
            Console.WriteLine("Success compile formatted syntax tree");
            return;
        }
        else
            Console.WriteLine("failed to compile formatted syntax tree");


        // Try to serialize and parse
        StringBuilder sb = new StringBuilder();
        using (StringWriter writer = new StringWriter(sb))
        {
            formattedNode.WriteTo(writer);
        }
        var treeAsString = sb.ToString();
        var stParsed = SyntaxFactory.ParseSyntaxTree(treeAsString);
        assembly = CompileAndLoad(stParsed);
        if (assembly != null)
        {
            Console.WriteLine("Success compile parsed syntax tree");
            return;
        }   
        else
            Console.WriteLine("failed to compile formatted syntax tree");

    }

    private static Assembly CompileAndLoad(SyntaxTree st)
    {
        var compilation
            = CSharpCompilation.Create("TestRoslyn.dll",new SyntaxTree[] { st },null,DefaultCompilationOptions);
        compilation = compilation.WithReferences(DefaultReferences);
        using (var stream = new MemoryStream())
        {
            EmitResult result = compilation.Emit(stream);
            if (result.Success)
            {
                var assembly = Assembly.Load(stream.GetBuffer());
                return assembly;
            }
            return null;
        }
    }