I’ve got a class (Request) that I want to convert to another one (Message) where the properties are of different types. I need to validate that the types are correct and can be parsed correctly, and log when the request is invalid.

How can I use ILogger in a public static class? Should I just create a public class with a method for the mapping instead?

Request class:

public class Request
{
    [Required]
    [Range(0, 99)]
    public int TillNumber { get; set; }
    
    [Required]
    [StringLength(6, MinimumLength = 4)]
    public string StoreCode { get; set; }

    [Required]
    public string ItemNumber { get; set; }
}

Message class:

public class Message
{
  public int TillNumber { get; set; }
  public int StoreCode { get; set; }
  public ItemCode Item { get; set; }
}

Extension class:

public static class DirectoryEnquiryExtensions
{
    public static Message ToMessage (this Request request)
    {

        var tillNumber = request.TillNumber;
        var storeCode = request.StoreCode;

        var successfullyParsed = int.TryParse(request.StoreCode, out int storeCode);
        if (!successfullyParsed)
        {
            logger.LogError("Not a valid store code {0}", request.StoreCode);
            return null;
        }
        
        ItemCode itemCode;
        if (!ItemCode.TryParse(request.ItemNumber, out itemCode))
        {
            logger.LogError("Not a valid item code {0}", request.ItemNumber);
            return null;
        }

        var message = new Message()
                            {
                                TillNumber = tillNumber,
                                StoreCode = storeCode,
                                ItemCode = itemCode
                            };
        return message;
    }
}