In Minimal API, there are binding issues when using `FromForm`.

[chipeng1023]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

public class Test
{
public int? ID { get; set; }
public string Code { get; set; }
[Required]
public string Name { get; set; }
public DateOnly? Birthday { get; set; }
public DateTime? AddTime { get; set; }
public IFormFile File { get; set; }
public IFormFile[] Files { get; set; }
public static ValueTask BindAsync(HttpContext context) { return ValueTask.FromResult(new Test()); }
}

public static IResult SubmitForm([FromForm] Test test, [NotNull] string flag)
{
//todo
}

1、An empty string cannot be bind to a value type property.

Microsoft.AspNetCore.Http.BadHttpRequestException: The value '' is not valid for 'Birthday'.
at Microsoft.AspNetCore.Http.RequestDelegateFactory.Log.FormDataMappingFailed(HttpContext httpContext, String parameterTypeName, String parameterName, FormDataMappingException exception, Boolean shouldThrow)
at lambda_method78(Closure, Object, HttpContext, Object)
at Microsoft.AspNetCore.Http.RequestDelegateFactory.<>c__DisplayClass103_2.<b__2>d.MoveNext()`

2、IFormFile[] Files is null

Expected Behavior

No response

Steps To Reproduce

No response

Exceptions (if any)

No response

.NET Version

net9.0

Anything else?

No response

[captainsafia]

@chipeng1023 Thanks for filing this issue!

I believe the first problem you are seeing is a dupe of #52195 which will be resolved in .NET 10. The shared form binding layer now treats empty strings as null for types like DateOnly.

As for the second issue, do you have success when you use IFormFileCollection as the property type?

[chipeng1023]

@captainsafia
use IFormFileCollection will get all files

example:
public IFormFileCollection Files { get; set; }

running results:

[chipeng1023]

@captainsafia
this is my custom model binding, that I can get the correct file.