External types ([CreateDtoFor] / [UpdateDtoFor])

External types ([CreateDtoFor] / [UpdateDtoFor])

For classes you don’t control (e.g. from a NuGet package), use separate attributes for create and update:

// External class you can't modify
public class ExternalOrder
{
    public int Id { get; set; }
    public string ProductName { get; set; }
    public decimal Price { get; set; }
    public int Quantity { get; set; }
    public string? Notes { get; set; }
}

// Create DTO — ignore Id, require ProductName
[CreateDtoFor(typeof(ExternalOrder), Ignore = new[] { "Id" }, Required = new[] { "ProductName" })]
public partial record CreateOrderRequest;

// Update DTO — ignore Id
[UpdateDtoFor(typeof(ExternalOrder), Ignore = new[] { "Id" })]
public partial record UpdateOrderRequest;

The generator produces a partial record with PatchField properties for all non-ignored properties from the target type.

• [CreateDtoFor] generates: Validate() (checks Required fields) + ToEntity()
• [UpdateDtoFor] generates: Validate() (null checks only) + ApplyTo(target)

You control the class name, which properties to ignore, and which to make required.

Renaming properties

Use [DtoName("newName")] on the property, or fluent b.ForType<T>().Property(p => p.X).RenameTo("newName") — see Fluent configuration.