.NET 核心 - System.Private.CoreLib.dll 与 System.Runtime

Question

In a .NET Core App, if I do

typeof(DateTime).Assembly.Location

I get

C:\Program Files\do.net\shared\Microsoft.NETCore.App\3.1.4\System.Private.CoreLib.dll

But the documentation for the DateTime struct says the assembly is System.Runtime.dll

I am trying to locate the XML Documentation file for DateTime . I cannot locate a System.Private.CoreLib.xml on my system but a System.Runtime.xml does accompany the System.Runtime.dll file in its folder (per XML documentation convention).

How does System.Private.CoreLib.dll relate to System.Runtime.dll ?

I am trying to use Roslyn to grab the XML <Summary> tag content, (similar to a hover tooltip in Visual Studio) but I cant see how to associate a Type with the location of the XML documentation?

Answer 1

System.Private.CoreLib.dll is the assembly that contains the core types of the .NET runtime, including the System namespace types such as DateTime. System.Runtime.dll is a separate assembly that contains types that are used by the runtime, but are not considered part of the core runtime itself.

The XML documentation for the DateTime struct is included in System.Private.CoreLib.xml, which is located in the same folder as System.Private.CoreLib.dll.

To associate a Type with the location of its XML documentation, you can use the XmlDocCommentProvider class from the Microsoft.CodeAnalysis.CSharp.DocumentationComments namespace. Here is an example of how you can use it to retrieve the XML documentation for the DateTime struct:

using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.CSharp.DocumentationComments;

// ...

var type = typeof(DateTime);

var assembly = type.Assembly;

var xmlDocCommentProvider = XmlDocCommentProvider.Create(assembly);

var docComment = xmlDocCommentProvider.GetDocumentationComment(type);

// Extract the summary element from the XML documentation
var summaryElement = docComment.DescendantNodes().OfType<XmlElementSyntax>().FirstOrDefault(x => x.StartTag.Name.ToString() == "summary");

if (summaryElement != null)
{
    var summaryText = summaryElement.GetText().ToString();
}

Answer 2

Ever since the introduction of .NET Standard, System.Runtime is an important assembly that forwards types to the actual assemblies (like System.Private.CoreLib.dll ) with their defitions,

https://learn.microsoft.com/en-us/do.net/standard/assembly/type-forwarding

There are tons of similar questions like this .

To learn more, use a tool like ILSpy to decompile System.Runtime and locate the type forwarding statements.