c#如何将sql数据库中多条出生日期转换成年龄

Question

 public class Person
        {
            public String Name;
            public DateTime birthday;
            public Int32 Age;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            database db = new database();
            string sql = "select * from JZK_pat where times=1";
            SqlDataReader mydr;
            db.runsql(sql, out mydr);
            while (mydr.Read())
            {
                Person item = new Person();
                int index = mydr.GetOrdinal("birthday");
                item.birthday = mydr.IsDBNull(index) ? new DateTime("1900-01-01") : mydr.GetDateTime(index);
                item.Age = DateTime.Now.Year - item.birthday.Year;
                listBox1.Items.Add(item);
            }
            mydr.Close();  
        }

sql数据库中有多条数据，字段名包括（姓名，性别，出生日期）

想用winform程序的textbox.Item显示出所有数据，但显示的格式为每一行（姓名，性别，年龄）

自己做的是SqlDataReader，但在while循环里无法实现多条出生日期转换成年龄

我是新手，请大神们指导一下，谢谢

Answer 1

字符串用 DateTime.Parse转，而不是new DateTime，ide会有参数类型提示，除非你用记事本来编写代码
 

public int GetAgeByBirthdate(DateTime birthdate)
    {
        DateTime now = DateTime.Now;
        int age = now.Year - birthdate.Year;
        if (now.Month < birthdate.Month || (now.Month == birthdate.Month && now.Day < birthdate.Day))
        {
            age--;
       }
       return age < 0 ? 0 : age;
   }
public class Person
{
public String Name;
public DateTime birthday;
public Int32 Age;
}


private void button1_Click(object sender, EventArgs e)
{
database db = new database();
string sql = "select * from JZK_pat where times=1";
SqlDataReader mydr;
db.runsql(sql, out mydr);
while (mydr.Read())
{
Person item = new Person();
int index = mydr.GetOrdinal("birthday");
item.birthday = mydr.IsDBNull(index) ? DateTime.Parse("1900-01-01") : mydr.GetDateTime(index);

item.Age =GetAgeByBirthdate(item.birthday);

listBox1.Items.Add(item);
}



mydr.Close();

}