DateOnly not supported

[Ashthos]

The DateOnly data type causes a NotSupportedException to be thrown when calling ParseArguments.

v2.9.1 from Nuget.

public class CommandLineOptions
  {
      [Option('v', "verbose", Required = false, HelpText = "Set output to verbose messages.")]
      public bool Verbose { get; set; }

      [Option('d', "business-date", Required = true, HelpText = "The date (yyyy-mm-dd) to run the process for.")]
      public DateTime Works { get; set; }

      [Option('e', "run-date", Required = true, HelpText = "The date (yyyy-mm-dd) to run the process for.")]
      public DateOnly Fails { get; set; }
  }

Workaround: Use DateTime instead and do an explicit conversion when property is used DateOnly.FromDateTime(value);

[IanKemp]

Yeah, this is because Microsoft added DateOnly and TimeOnly in .NET 6 but stupidly neglected to add built-in TypeConverters for them. This will be fixed in .NET 7 but until then:

• add DateOnlyConverter.cs to your project (you will need to adjust the SR stuff)
• bind it to DateOnly via TypeDescriptor before you invoke CommandLineParser (so ideally, first line in Program.cs):

TypeDescriptor.AddAttributes(typeof(DateOnly), new[] { new TypeConverterAttribute(typeof(DateOnlyConverter)) });

• use DateOnly as you need for your command-line options
• when .NET 7 comes out and you upgrade your project to use it, simply delete DateOnlyConverter.cs and the call to TypeDescriptor.AddAttributes