XML comments are not shown in Swagger documentation, is this bug in swagger?

In my case, the XML comments were missing in Swagger because the API itself and the model classes are in different assemblies.

I solved it like this:

public void ConfigureServices(IServiceCollection services)
{
    // ...

    services.AddSwaggerGen(c =>
    {
        // ...other stuff

        // include API xml documentation
        var apiAssembly = typeof(SomeApiClass).Assembly;
        c.IncludeXmlComments(GetXmlDocumentationFileFor(apiAssembly));

        // include models xml documentation
        var modelsAssembly = typeof(ModelsProject.SomeModelClass).Assembly;
        c.IncludeXmlComments(GetXmlDocumentationFileFor(modelsAssembly));
    });
}

private static string GetXmlDocumentationFileFor(Assembly assembly)
{
    var documentationFile = $"{assembly.GetName().Name}.xml";
    var path = Path.Combine(AppContext.BaseDirectory, documentationFile);

    return path;
}

Of course, don't forget to enable XML documentation in both .csproj files as well.

Do not include any ampersands in your remarks. If you do, you documentation will not be displayed.

Try doing

1. remove old
2. Right-click the project in Solution Explorer and select Edit <project_name>.csproj.
3. Manually add the highlighted lines to the .csproj file

<PropertyGroup>
    <GenerateDocumentationFile>true</GenerateDocumentationFile>
    <NoWarn>$(NoWarn);1591</NoWarn>
</PropertyGroup>

4. generate new file

https://learn.microsoft.com/en-us/samples/aspnet/aspnetcore.docs/getstarted-swashbuckle-aspnetcore/?tabs=visual-studio

For .NET 6 another way of doing it base on this Microsoft docs:

Opening Project file .csproj and add this lines

<PropertyGroup>
  <GenerateDocumentationFile>true</GenerateDocumentationFile>
  <NoWarn>$(NoWarn);1591</NoWarn>
</PropertyGroup>

Then in Program file Change this:

  builder.Services.AddSwaggerGen();

To this

builder.Services.AddSwaggerGen(options =>
{
    // using System.Reflection;
    var xmlFilename = $"{Assembly.GetExecutingAssembly().GetName().Name}.xml";
    options.IncludeXmlComments(Path.Combine(AppContext.BaseDirectory, xmlFilename));
});

In my case, the comments weren't appearing because I had put a url inside the remarks. Not sure why it broke it, but once I had removed the url everything worked.

At my case, I set always copy for xml generated at build option.

and at startup at AddSwaggerGen option, I add the some code, if file exist, generate comments by IncludeXmlComments :

        services.AddSwaggerGen((opt) =>
        {
            opt.SwaggerDoc("v1", new OpenApiInfo { Title = "API", Version = "v1",
                Description = "Your app desc",
                Contact = new OpenApiContact()
                {
                    Name = "@yourname",
                    Url = new System.Uri("yoursite.com"),
                }
            });

            var xmlFile = $"{Assembly.GetExecutingAssembly().GetName().Name}.xml";
            var xmlPath = Path.Combine(AppContext.BaseDirectory, xmlFile);

            if (File.Exists(xmlPath))
                opt.IncludeXmlComments(xmlPath);
        });

I also faced this issue for getting XML comments for controllers in the swagger page UI in .net6 core. I found a simple solution by enabling the "XML Documentation file path" option in the properties of the project. you can follow below mentioned simple steps:

• Add the functionality while configuring thr swagger in program.cs or startup.cs

  `builder.Service.AddSwaggerGen (c => { c.SwaggerDoc("v1", new OpenApiInfo { Title = "JWTToken_Auth_API", Version = "v1" }); c.IncludeXmlComments(Path.Combine(AppContext.BaseDirectory, $"{Assembly.GetExecutingAssembly().GetName().Name}.xml")); });

• Right-click on the project and open the properties.

• Go to Build -> Output -> Enable "Documentation file". (Also, you can set your path for XML documentation file or the default location will be used) enter image description here