Can this tool obtain the namespace of each element in the C# file?

[yz-qiang]

Hi, Roslyn is a nice job, thanks for your contribution.
Here, I have a question about code analysis.
Given a C# code file, for example:

"using System;
namespace std
{
class HelloWorld
{
static void Main(string[] args)
{
Console.WriteLine("Hello World!");
Console.ReadKey();
}}}
"

Whether Roslyn can output a file that each code element be resolved into the fully-qualified name？Just Like

"
using System;
namespace std
{
class HelloWorld
{
static void Main(string[] args)
{
System.Console.WriteLine("Hello World!");
System.Console.ReadKey();
}}}
“

If possible, can you show me how to implement this feature?
Thank you very much.

[jasonmalinowski]

@yz-qiang So yes, absolutely, that can be done. The one thing of course to keep in mind is you do need some project surrounding your source file for us to even know what "Console" is, since that comes from the framework.

Was there a specific thing you were having issues with?

[CyrusNajmabadi]

See the docs that were linked. It's in this section:
https://learn.microsoft.com/en-us/dotnet/csharp/roslyn-sdk/get-started/semantic-analysis?source=recommendations#binding-a-name

I recommend using discord for this conversation. It will likely go much faster.

[yz-qiang]

Thanks for your reply.
According to your suggestion, I am trying to use the semantic model to achieve my goal.
However, I still have some questions. My code is the following (Note: My question noted in the code. ):

using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using System.Linq;
using System;

namespace SyntaxWalker
{
    class semanticModel
    {
        const string programText = @"using Microsoft.CodeAnalysis;
                                    using Microsoft.CodeAnalysis.CSharp;
                                    using Microsoft.CodeAnalysis.CSharp.Syntax;
                                    using System;
                                    using System.Linq;
                                    namespace ClassLibrary1 {
                                        class UsingCollector {
                                            const string programText = ...;
                                                static void Main(string[] args)
                                            {
                                                var tree = CSharpSyntaxTree.ParseText(programText);
                                                var Mscorlib = MetadataReference.CreateFromFile(typeof(object).Assembly.Location);
                                                var compilation = ....;
                                                var methodSyntax = tree.GetRoot().DescendantNodes().OfType<MethodDeclarationSyntax>().First();
                                                Console.WriteLine(""Hello world"");
                                            }
                                        }
                                    }";
        static void Main(string[] args) {
            var tree = CSharpSyntaxTree.ParseText(programText);
            var Mscorlib = MetadataReference.CreateFromFile(typeof(object).Assembly.Location);
            var compilation = CSharpCompilation.Create("MyCompilation",
                    syntaxTrees: new[] { tree }, references: new[] { Mscorlib });
            var model = compilation.GetSemanticModel(tree);

            //Looking at the first method symbol
            var expression = tree.GetRoot().DescendantNodes().OfType<ExpressionStatementSyntax>().First();
            var expressionState = expression.Expression;
            var expressionSymbol = model.GetSymbolInfo(expressionState);
            var expressionSymbol_string = expressionSymbol.Symbol.ToString();

  // ① #### Here, the fully qualified name of `Console.WriteLine()' could be printed correctly, that is, System.Console.WriteLine()
            Console.WriteLine(expressionSymbol_string);  

            var invocation = tree.GetRoot().DescendantNodes().OfType<InvocationExpressionSyntax>().First();
            var invocationState = invocation.Expression;  // Here, the output is `CSharpSyntaxTree.ParseText(programText)`
            var invocationSymbol = model.GetSymbolInfo(invocationState);
            var invocationSymbol_string = invocationSymbol.Symbol.ToString();

             // ② #### However, the output is Null.  I don't know why.
             Console.WriteLine(invocationSymbol_string);

        }
    }
}

Otherwise, For ①, If I replace the Console.WriteLine(""Hello world""); with Console.WriteLine(methodSyntax.ToString()); in programText. The output of expressionSymbol_string will also be Null. It feels a little weird.

Intuitively, I find this approach a little complicated. Because first, I need to get the fully qualified name of a code element and then convert the simple name in the code to a fully qualified name.
Alternatively: is there another (more suited?) way to do that?

[CyrusNajmabadi]

I recommend discord.

[yz-qiang]

Thanks for your reply.
What is discord? Could you tell me more about it？
And can you tell me what the problem is with my code?

[rafael-f]

This is Discord -> http://aka.ms/discord-csharp-roslyn

(Chat app)