可选属性中的MVC必需属性

我有两个实体:

public class ParentThing
{
    [Key]
    public int Id { get; set; }

    [Required]
    public ChildThing TheFirstThing { get; set; }

    public ChildThing TheSecondThing { get; set; }
}

public class ChildThing
{
    [Key]
    public int Id { get; set; }

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

    public string Name { get; set; }
}

和视图模型:

public class ParentViewModel
{
    public string Message { get; set; }

    public ParentThing ParentThing { get; set; }
}

和一个观点:

@using (@Html.BeginForm())
{
    Code 1
    @Html.EditorFor(model => model.ParentThing.TheFirstThing.Code)

    Name 1
    @Html.EditorFor(model => model.ParentThing.TheFirstThing.Name)

    Code 2
    @Html.EditorFor(model => model.ParentThing.TheSecondThing.Code)

    Name 2
    @Html.EditorFor(model => model.ParentThing.TheSecondThing.Name)

    
}

在我的帖子中,我将ParentThing添加到上下文并尝试保存更改.我在ParentThing的TheSecondThing属性的Code属性上收到验证错误,因为它是必需的.

保存包含必需属性的可选属性有哪些替代方法？