Get inner details of the TYPE of a method parameter using Roslyn

Question

I'm trying to find out if there is a way to get the inner details of the TYPE of a method parameter.

Say a method has the below definition

public void method1(Type1 param1, Type2 param2)
{
   ...
   ...
}

And Type1 has the below definition

public class Type1
{
    public int prop1 {get; set;}
    public string prop2 {get; set;}
    public double prop3 {get; set;}
}

Then what I'm looking to get out of my sample tool is the list of properties of the class Type1. That is, I'm expecting my output to be

prop1 
prop2 
prop3

I could get a reference to the parameter by doing a param.Type but it is of type IdentifierNameSyntax. I'm able to get the name from it (Type1 in this case) but not able to dig deeper INTO Type1 to get the properties.

Is there any simple way to get that which I'm not yet aware of? Or do I have to do a search in the entire solution again using the name of the type that I got?

Thanks a lot!

P.S.: I did get a thought of using Reflection but all I have is a string (Type1) and not the actual TYPE. Not sure if I can use this or not.

Update-1: This question seems to be mildly close to what I'm expecting but from what I understand, the user only wants the name of the parameter type, not it's inner details.

Update-2: Adding sample code from my tool below. Unfortunately, I cannot post the actual code but the below sample is basically what I'm trying to do. Update-2: Adding sample code from my tool below. Unfortunately, I cannot post the actual code but the below sample is basically what I'm trying to do.

var methodNode = (MethodDeclarationSyntax)node;
string paramClassName = string.Empty;

foreach (var param in methodNode.ParameterList.Parameters)
{
    paramClassName = param.Type.ToFullString();
    //GET Class details from the above class name
    GetInnerDetailsOfClassFromClassName(paramClassName);   //any way to do this?
}

You probably want to be looking at the *symbols* rather than the *syntax*. It would be easier to help you with that if you could show us the context of your code... — Jon Skeet, Aug 13 '15 at 09:54
Right - have a look at the question Serj-Tm linked to. Basically it's the same deal - you want to get the symbol info via the semantic model. — Jon Skeet, Aug 13 '15 at 10:19
@Serj-Tm The link that you shared is basically doing a full solution search again. But I was wondering if there was another way to do it because, when my program is at the above given code, it is already in the middle of a search. Hence want to avoid initiating another search inside a search :) — Amogh Natu, Aug 13 '15 at 10:19
@AmoghNatu Create semantic model before search and put semantic model to search — Serj-Tm, Aug 13 '15 at 10:26

score 3 · Answer 1 · answered Aug 13 '15 at 12:23

3

Once you find the ParameterSyntax, use SemanticModel.GetDeclaredSymbol to get the IParameterSymbol, and then look at its Type to get the ITypeSymbol you are interested in.

answered Aug 13 '15 at 12:23

Kevin Pilch

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Yes that is precisely what I did. :) thanks :) and thanks to @Serj-Tm too for his suggestion. I had not looked at the Symbols. Will post my code so that it can help others. – Amogh Natu Aug 13 '15 at 13:09

score 0 · Accepted Answer · answered Aug 13 '15 at 14:05

Thanks to @Serj-Tm, @KevinPilch-Bisson and @JonSkeet. Your suggestions of using Symbols worked. This is my code below that returned the result I was expecting.

var methodNode = (MethodDeclarationSyntax)node;
string modelClassName = string.Empty;

foreach (var param in methodNode.ParameterList.Parameters)
{
    var metaDataName = document.GetSemanticModelAsync().Result.GetDeclaredSymbol(param).ToDisplayString();
//'document' is the current 'Microsoft.CodeAnalysis.Document' object
    var members = document.Project.GetCompilationAsync().Result.GetTypeByMetadataName(metaDataName).GetMembers();
    var props = (members.OfType<IPropertySymbol>());

    //now 'props' contains the list of properties from my type, 'Type1'
    foreach (var prop in props)
    {
        //some logic to do something on each proerty
    }

}

Hope this helps!

Get inner details of the TYPE of a method parameter using Roslyn

2 Answers2