Given a class in Visual Studio, how to find out which dll contains it?

Question

Working on modifying an existing .NET project. Given a C# class in Visual Studio, how can I find out which DLL has it?

The problem is that I want to use a method in this class in a new project so I need to find the correct DLL to add as a reference for the new project.

Answer 1

Search for your class name in the object browser (Menu View -> Object Browser). The assembly information window will contain the dll complete path.

Answer 2

You can see the assembly in the project properties. The output name of the DLL (which is what a Class Library project produces) is specified in there.

Answer 3

There are some tools like ReSharper that will suggest adding using statements and even add a reference to the project. It seems you don't have something like that.

Adding a reference for a Microsoft class

In that case (before I had tools), I google for

class <ClassName> site:msdn.microsoft.com

eg

class Process site:msdn.microsoft.com

which brings me to the Process class . On the MSDN page, it lists the namespace and assembly:

Namespace:  System.Diagnostics
Assembly:  System (in System.dll)

Adding a reference of your own class in a different project

• Open the class definition (source code)
• Open the Solution Explorer
• Click the "Sync with active document" button
• 
• Move up to the project
• Open properties ( Alt + Enter )
• Look at Application/Assembly Name

Answer 4

This can be rather frustrating and irritating - I found myself in a situation where I needed an answer to the OP's question and none of the above answers worked for me.

I had a program that imported some Roslyn DLLs. Later, after I'd become unsure as to which DLLs were really necessary, I was trying to find out which classes were in which DLLs.

For example, my program referenced class MSBuildWorkspace . Navigating to the class declaration I can see the namespace name, and the fully qualified name of the class is Microsoft.CodeAnalysis.MSBuild.MSBuildWorkspace .

Opening the Object Browser, as suggested by @Spell, and searching for Microsoft.CodeAnalysis.MSBuild.MSBuildWorkspace results in "Search found no results", which I'm guessing must be due to a bug in Visual Studio.

Fortunately, searching for just MSBuildWorkspace does find the class, but it still didn't tell me which DLL contains the class.

So what I needed to do was to click on the class name, which is shown as a link, in the smallish panel in the lower right part of Object Browser. This results in the left panel switching to a view of the DLLs and the classes they contain. Now I could see that class MSBuildWorkspace was in DLL Microsoft.CodeAnalysis.Workspaces , and right-clicking on that and selecting Copy and pasting the result into a text editor provided the full path to the DLL.