c# - 查找属于InvocationExpressionSyntax的UsingDirectiveSyntax

在下面的代码中，“console.writeline”调用需要“system”使用指令才能工作。我已经有了“using system”的usingdirectivesyntax对象和“console.writeline”的invocationsyntax对象。但是，使用roslyn，我怎么知道调用表达式syntax和usingdirectivesyntax对象是属于彼此的呢？

using System;
public class Program
{
   public static void Main()
   {
      Console.WriteLine("Hello World");
   }
}

最佳答案

InvocationExpressionSyntax的方法符号有一个成员，该成员应等于从using指令的符号检索中获得的命名空间符号。这里的技巧是使用ContainingNamespace成员作为查询语义模型的起点，因为整个Name不会给您一个符号。
Try this LINQPad query（或将其复制到控制台项目中），您将在查询的最后一行得到UsingDirectiveSyntax。

// create tree, and semantic model
var tree = CSharpSyntaxTree.ParseText(@"
    using System;
    public class Program
    {
       public static void Main()
       {
          Console.WriteLine(""Hello World"");
       }
   }");
var root = tree.GetRoot();

var mscorlib = MetadataReference.CreateFromFile(typeof(object).Assembly.Location);
var compilation = CSharpCompilation.Create("SO-39451235", syntaxTrees: new[] { tree }, references: new[] { mscorlib });
var model = compilation.GetSemanticModel(tree);

// get the nodes refered to in the SO question

var usingSystemDirectiveNode = root.DescendantNodes().OfType<UsingDirectiveSyntax>().Single();
var consoleWriteLineInvocationNode = root.DescendantNodes().OfType<InvocationExpressionSyntax>().Single();

// retrieve symbols related to the syntax nodes

var writeLineMethodSymbol = (IMethodSymbol)model.GetSymbolInfo(consoleWriteLineInvocationNode).Symbol;
var namespaceOfWriteLineMethodSymbol = (INamespaceSymbol)writeLineMethodSymbol.ContainingNamespace;

var usingSystemNamespaceSymbol = model.GetSymbolInfo(usingSystemDirectiveNode.Name).Symbol;

// check the namespace symbols for equality, this will return true

namespaceOfWriteLineMethodSymbol.Equals(usingSystemNamespaceSymbol).Dump();