Cannot bind StringValues for HTTP request header with Minimal APIs

[GihanSoft]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

using FromHeader attribute on minimal API parameter with type StringValues type produce error on build and analyze

Program.cs(7,18,7,70): error ASP0020: Parameter 'ifMatch' of type StringValues should define a bool TryParse(string, IFormatProvider, out StringValues) method, or implement IParsable<StringValues> (https://aka.ms/aspnet/analyzers)

Expected Behavior

No response

Steps To Reproduce

build this code:

using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Primitives;

var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();

app.MapGet("/", ([FromHeader(Name = "If-Match")] StringValues ifMatch) => ifMatch);

app.Run();

Exceptions (if any)

No response

.NET Version

8.0.202

Anything else?

there is an issue (#40752) that address same bug in previous versions. It seems it's returned again

[captainsafia]

@GihanSoft I believe this issue is likely in the analyzers that produce the ASP0020 warning. The actual parameter binding implementation in minimal APIs does support binding correctly to StringValues from the header (as indicated by the original issue).

For now, you should be safe to disable this warning around the impacted source.

#pragma warning disable ASP0020 // Complex types referenced by route parameters must be parsable
app.MapGet("/", ([FromHeader(Name = "If-Match")] StringValues ifMatch) => ifMatch);
#pragma warning restore ASP0020 // Complex types referenced by route parameters must be parsable

I'll leave this issue open in the backlog for tracking.