我在阅读here有关在C#中创建不可变类的信息。有人建议我采用这种方式来实现真正的不变性:
private readonly int id;
public Person(int id) {
this.id = id;
}
public int Id {
get { return id; }
}
我了解这一点,但是如果我想进行一些错误检查,该如何抛出异常呢?给定以下课程,我只能考虑这样做:
private readonly int id;
private readonly string firstName;
private readonly string lastName;
public Person(int id,string firstName, string lastName)
{
this.id=id = this.checkInt(id, "ID");
this.firstName = this.checkString(firstName, "First Name");
this.lastName = this.checkString(lastName,"Last Name");
}
private string checkString(string parameter,string name){
if(String.IsNullOrWhiteSpace(parameter)){
throw new ArgumentNullException("Must Include " + name);
}
return parameter;
}
private int checkInt(int parameter, string name)
{
if(parameter < 0){
throw new ArgumentOutOfRangeException("Must Include " + name);
}
return parameter;
}
那是正确的方法吗?如果没有,如何在不可变类中引发异常?
最佳答案
我将内联这两个私有方法:
private readonly int id;
private readonly string firstName;
private readonly string lastName;
public Person(int id, string firstName, string lastName)
{
if(String.IsNullOrWhiteSpace(firstName))
throw new ArgumentNullException("firstName");
if(String.IsNullOrWhiteSpace(lastName))
throw new ArgumentNullException("lastName");
if(id < 0)
throw new ArgumentOutOfRangeException("id");
this.id=id;
this.firstName = firstName ;
this.lastName = lastName ;
}