Strongly Typed Ids

[DermotMurphy]

I am trying to map a Domain Entity (User) to a DTO (UserDto) using this mapper:

[Mapper]
public static partial class UserMapper
{
[MapProperty(nameof(User.Id.Value), nameof(UserDto.Id))]
public static partial UserDto MapUserToDto(User user);
}

public class User
{
public UserId Id { get; set; }
public required string FirstName { get; set; }

public required string LastName { get; set; }

}

public readonly record struct UserId(Guid Value);

public class UserDto
{
public Guid Id { get; set; }
public string? FirstName { get; set; }

public string? LastName { get; set; }


#region Overrides of Object

public override string ToString()
{
    return $"Id: {Id}, FirstName: {FirstName}, LastName: {LastName}";
}

#endregion

}

Program.cs looks like this:

var user = new User
{
Id = new UserId(Guid.NewGuid()),
FirstName = "James",
LastName = "Kirk"
};

var dto = UserMapper.MapUserToDto(user);

Console.WriteLine(dto);

I am getting two identical errors:

Severity Code Description Project File Line Suppression State
Error RMG006 Specified property Value on source type ConsoleMappingObjects.User was not found ConsoleMappingObjects E:\Source\Repos\ConsoleMappingObjects\ConsoleMappingObjects\UserMapper.cs 8 Active

Does this MappingAttribute do what I believe it ought to?

[MapProperty(nameof(User.Id.Value), nameof(UserDto.Id))]

I am expecting the Value property of the Id property on the User object to be mapper to the Id property on the UserDto object.

Am I missing something?

[latonz]

The problem is that nameof only resolves the symbol it references, for User.Id.Value it is Value but you want to reference the property path Id.Value.

[MapProperty(nameof(User.Id.Value), nameof(UserDto.Id))]
resolves to
[MapProperty("Value", "Id")]
but what you actually want is
[MapProperty("Id.Value", "Id")] or with nameof [MapProperty(new[] { nameof(User.Id), nameof(User.Id.Value) }, new[] { nameof(UserDto.Id) })].

[DermotMurphy]

Thanks Lars. Excellent explanation 👍

…

On Thu, 30 Mar 2023, 17:06 Lars, ***@***.***> wrote: The problem is that nameof only resolves the symbol it references, for User.Id.Value it is Value but you want to reference the property path Id.Value. [MapProperty(nameof(User.Id.Value), nameof(UserDto.Id))] resolves to [MapProperty("Value", "Id")] but what you actually want is [MapProperty("Id.Value", "Id")] or with nameof [MapProperty(new[] { nameof(User.Id), nameof(User.Id.Value) }, new[] { nameof(UserDto.Id) })]. — Reply to this email directly, view it on GitHub <#306 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ACPKZR4CBJPPFRHQ652LLHDW6WVRFANCNFSM6AAAAAAWNO75DA> . You are receiving this because you authored the thread.Message ID: ***@***.***>