C# Language Extension Methods Using Extension methods to create beautiful mapper classes
Example
We can create a better mapper classes with extension methods, Suppose if i have some DTO classes like
public class UserDTO
{
public AddressDTO Address { get; set; }
}
public class AddressDTO
{
public string Name { get; set; }
}
and i need to map to corresponding view model classes
public class UserViewModel
{
public AddressViewModel Address { get; set; }
}
public class AddressViewModel
{
public string Name { get; set; }
}
then I can create my mapper class like below
public static class ViewModelMapper
{
public static UserViewModel ToViewModel(this UserDTO user)
{
return user == null ?
null :
new UserViewModel()
{
Address = user.Address.ToViewModel()
// Job = user.Job.ToViewModel(),
// Contact = user.Contact.ToViewModel() .. and so on
};
}
public static AddressViewModel ToViewModel(this AddressDTO userAddr)
{
return userAddr == null ?
null :
new AddressViewModel()
{
Name = userAddr.Name
};
}
}
Then finally i can invoke my mapper like below
UserDTO userDTOObj = new UserDTO() {
Address = new AddressDTO() {
Name = "Address of the user"
}
};
UserViewModel user = userDTOObj.ToViewModel(); // My DTO mapped to Viewmodel
The beauty here is all the mapping method have a common name (ToViewModel) and we can reuse it several ways
