# roslyn中的if指令代码解析

Question

我试图使用Roslyn从我的CS文件中提取代码的一部分，我遇到了下面的问题。

我的C#文件代码：

    class ConditionalCompilationCode
    {
#if Condition2
            int test2=0; 
#endif
#if Condition1
            int test1=0; 
#endif

        public static void Main1(string[] args)
        {
            int test = 0;
#if Condition1
            test = 1;
#else
            test =2;
#endif

#if Condition2
            test =3;
#else
            test = 4;
#endif

        }
#if Condition2
            private void testmethod1()
        {
            test2 = 1;
        }
#endif
#if !Condition2
        private void testmethod2()
        {
            test1 = 1;
        }
#endif
#if Condition1
        private void testmethod3()
        {
            test1 = 1;
        }
#endif
#if !Condition1
            private void testmethod4()
        {
            test2 = 1;
        }
#endif
    }
}

我的罗斯林代码：

string fileContent = File.ReadAllText(fileName);

SyntaxTree syntaxTree = CSharpSyntaxTree.ParseText(fileContent);

var syntaxRootNode = syntaxTree.GetRoot();
            if (syntaxRootNode.GetFirstToken().Kind() == SyntaxKind.None)
                return;
            foreach (NamespaceDeclarationSyntax namespaceSyntax in syntaxRootNode.DescendantNodes().OfType<NamespaceDeclarationSyntax>().ToArray())
            {

                IEnumerable<SyntaxNode> nodeList = namespaceSyntax.ChildNodes();
                string className = null;
                foreach (SyntaxNode syntaxNode in nodeList)
                {
                    SyntaxKind kind = syntaxNode.Kind();
                    switch (kind)
                    {
                        case SyntaxKind.ClassDeclaration:
                            UpdateClassSignature(syntaxNode as TypeDeclarationSyntax);                            
                            break;
                        case SyntaxKind.EnumDeclaration:

                            break;
                        case SyntaxKind.InterfaceDeclaration:

                            break;
                        case SyntaxKind.StructDeclaration:

                            break;

                    }

                }

            }

    private void UpdateClassSignature(TypeDeclarationSyntax classDeclarationSyntax)
        {

            foreach (MemberDeclarationSyntax member in classDeclarationSyntax.Members)
            {
                SyntaxKind kind = member.Kind();
                switch (kind)
                {
                    case SyntaxKind.FieldDeclaration:
                        break;
                    case SyntaxKind.PropertyDeclaration:
                        break;
                    case SyntaxKind.MethodDeclaration:
                    case SyntaxKind.ConstructorDeclaration:
                    case SyntaxKind.DestructorDeclaration:
                        break;
                    case SyntaxKind.IndexerDeclaration:
                        ExtractIndexer(member as IndexerDeclarationSyntax, classSign);
                        break;
                    case SyntaxKind.DelegateDeclaration:
                        //TODO: Add Delegate Support.
                        break;
                    case SyntaxKind.OperatorDeclaration:
                    case SyntaxKind.ConversionOperatorDeclaration:
                        //Skip.
                        //TODO: Need to add operator suport.
                        break;
                    case SyntaxKind.EventFieldDeclaration:
                        //TODO: Add support to event.
                        break;
                    case SyntaxKind.EventDeclaration:
                        //TODO: Add support to event.
                        break;
                    case SyntaxKind.EnumDeclaration:
                        break;
                    case SyntaxKind.ClassDeclaration:
                        break;
                    case SyntaxKind.StructDeclaration:
                        break;
                    default:
                        break;
                }
            }
        }

在使用roslyn处理上述CS文件时，classDeclarationSyntax.Members中包含以下三个值：

1. MethodDeclarationSyntax MethodDeclaration 公共静态无效Main1(string[] args) { int test = 0；#if Condition1 test = 1；#else test =2；#endif #if Condition2 test =3；#Condition2 test = 4；#endif }
2. MethodDeclarationSyntax MethodDeclaration 私有void testmethod2() { test1 = 1；}
3. MethodDeclarationSyntax MethodDeclaration 私有void testmethod4() { test2 = 1；}

我的项目只有"Condition1“指令。只有当条件只有"Condition1“时，你才能帮助我获得密码吗？

提前谢谢。

Answer 1

您需要传递一个CSharpParseOptions，该WithPreprocessorSymbols()调用WithPreprocessorSymbols()将要定义的符号传递给解析器。