MVVM -从存储库类检索数据后在哪里格式化数据？

public class User
{
    public int Id { get; set; }
    public string Name { get; set; }
    public DateTime BirthDate { get; set; }
}

public class UserRepository
{
    public User GetUserById(int id)
    {
        // 模拟从数据库中检索用户数据
        return new User
        {
            Id = id,
            Name = "John Doe",
            BirthDate = new DateTime(1990, 5, 15)
        };
    }
}

public class UserViewModel
{
    private readonly UserRepository _userRepository;

    public UserViewModel(UserRepository userRepository)
    {
        _userRepository = userRepository;
    }

    public User User { get; private set; }

    public void LoadUser(int id)
    {
        User = _userRepository.GetUserById(id);
        FormatUserData();
    }

    private void FormatUserData()
    {
        if (User != null)
        {
            User.Name = User.Name.ToUpper();
            User.BirthDate = User.BirthDate.ToShortDateString();
        }
    }
}

<Window x:Class="MVVMExample.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="200" Width="200">
    <StackPanel>
        <TextBlock Text="User ID:"/>
        <TextBlock Text="{Binding User.Id}"/>
        <TextBlock Text="User Name:"/>
        <TextBlock Text="{Binding User.Name}"/>
        <TextBlock Text="Birth Date:"/>
        <TextBlock Text="{Binding User.BirthDate}"/>
    </StackPanel>
</Window>