How to specify the format of DateTime when xml serialization and deserialization?

[pedoc]

By searching, most of the solutions are as follows
Do not use the DateTime type, use string directly, and create a shadow field, so that you can control the format arbitrarily, the sample code is as follows

public class A{
[XmlElement("Time")]
public string _Time{get;set;}

[XmlIgnore]
public DataTime Time{
  get=>DateTime.Parse(_Time);
  set=>_Time=value.ToString("yyyy-MM-dd HH:mm:ss");
 }
}

Adding such helper fields serves no purpose other than to add confusion, is there a built-in mechanism to easily handle this?

thanks