I have two lists, studentList ( is already made and I have no problem with ) and studentList2 ( a list of data read from a csv file.)
The part of the code that works is the part where studentList1 is able to display the class students and the 5 objects. however as for studentList 2, I'm able to read from the csv file but unable to add the 2 students into a list and display it together with studentList 1.
I tried to apply the same concept from the first list (which is manually made) to the second list (read from csv file). but I can see it obviously doesn't work and I'm not sure on how to fix it.
This is what I've got so far:
using school;
using System.Reflection.PortableExecutable;
DateTime dob1 = new DateTime(2000, 10, 13);
Student s1 = new Student(1, "John Tan", "88552211", dob1);
DateTime dob2 = new DateTime(2001, 11, 01);
Student s2 = new Student(2, "Peter Lim", "85678141", dob2);
DateTime dob3 = new DateTime(2000, 01, 03);
Student s3 = new Student(3, "David Chan", "88555461", dob3);
DateTime dob4 = new DateTime(2000, 05, 07);
Student s4 = new Student(4, "Muhammed Faizal", "98762211", dob4);
DateTime dob5 = new DateTime(2000, 08, 09);
Student s5 = new Student(5, "Esther Eng", "83352245", dob5);
List<Student> studentList = new List<Student>();
studentList.Add(s1);
studentList.Add(s2);
studentList.Add(s3);
studentList.Add(s4);
studentList.Add(s5);
//call the method to display the student list
DisplayOutput(studentList);
studentList.Add(GetStudent());
DisplayOutput(studentList);
DisplayOutput(studentList2);
//method that displays all the students
static void DisplayOutput(List<Student> sList)
{
Console.WriteLine("");
//header id name tel dob
Console.WriteLine("{0,-5} {1,-17} {2,-10} {3,-20}",
"ID", "Name", "Tel", "Date of Birth");
//for loop to print the rest of the info
foreach (Student s in sList)
{
Console.WriteLine("{0,-5} {1,-17} {2,-10} {3,-20}",
s.ID, s.Name, s.Tel, s.DateOfBirth.ToString("dd/MM/yyyy"));
}
}
static Student GetStudent()
{
// prompt user for info
Console.Write("Enter id: ");
int id = Convert.ToInt32(Console.ReadLine());
Console.Write("Enter name: ");
string? name = Console.ReadLine();
Console.Write("Enter tel: ");
string? tel = Console.ReadLine();
Console.Write("Enter Date of Birth: ");
DateTime dateOfBirth = Convert.ToDateTime(Console.ReadLine());
Console.WriteLine("");
return new Student(id, name, tel, dateOfBirth);
}
//list from the csv
List<Student> studentList2 = new List<Student>();
studentList2.Add(s6);
studentList2.Add(s7);
string[] csvLines = File.ReadAllLines("Students.csv");
string[] heading = csvLines[0].Split(',');
// Read and display lines from the file until the end of
// the file is reached.
for (int i = 1; i < csvLines.Length; i )
{
string[] data = csvLines[i].Split(',');
//Console.WriteLine("{0,-5} {1,-17} {2,-10} {3,-20}",
// data[0], data[1], data[2], data[3]);
Student s6 = new Student(data[0], data[1], data[2], data[3]);
Student s7 = new Student(data[0], data[1], data[2], data[3]);
}
and this is my class
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace school
{
class Student
{
private int id;
public int ID
{
get { return id; }
set { id = value; }
}
private string? name;
public string? Name
{
get { return name; }
set { name = value; }
}
private string? tel;
public string? Tel
{
get { return tel; }
set { tel = value; }
}
private DateTime dateOfBirth;
public DateTime DateOfBirth
{
get { return dateOfBirth; }
set { dateOfBirth = value; }
}
// constructor
public Student(int d, string? n, string? t, DateTime dob)
{
ID = d;
Name = n;
Tel = t;
DateOfBirth = dob;
}
// methods
public string StudentFullName()
{
return ID " " Name " " Tel " " DateOfBirth;
}
}
}
here is the csv file contents:
ID,Name,Phone,Date of Birth
10,Alan Tan,98552211,13/5/2001
20,Bobby Lim,95678141,8/11/2001
CodePudding user response：
What I understood from your last comment, you need to do this.
//studentList2.Add(s6); //comment these lines
//studentList2.Add(s7);
string[] csvLines = File.ReadAllLines("Students.csv");
string[] heading = csvLines[0].Split(',');
// Read and display lines from the file until the end of
// the file is reached.
for (int i = 1; i < csvLines.Length; i )
{
string[] data = csvLines[i].Split(',');
//Console.WriteLine("{0,-5} {1,-17} {2,-10} {3,-20}",
// data[0], data[1], data[2], data[3]);
//Student s6 = new Student(data[0], data[1], data[2], data[3]); //also comment these lines
//Student s7 = new Student(data[0], data[1], data[2], data[3]);
studentList2.Add(new Student(data[0], data[1], data[2], data[3]));
}
CodePudding user response：
There seem to be two issues in your code.
The studentList2 is adding student object s6 and s7 before they are initialised.(This should have come during compile time errors). You need to initialise it before adding it to the list.
The data you are reading needs to be converted to int and datetime respectively(data[0] and data[3]) while creating s6 and s7. Refer to the code pasted above.
List<Student> studentList2 = new List<Student>(); string[] csvLines = File.ReadAllLines("Students.csv"); string[] heading = csvLines[0].Split(','); // Read and display lines from the file until the end of // the file is reached. for (int i = 1; i < csvLines.Length; i ) { string[] data = csvLines[i].Split(','); //Console.WriteLine("{0,-5} {1,-17} {2,-10} {3,-20}", // data[0], data[1], data[2], data[3]); Student s6 = new Student(Convert.ToInt32(data[0]), data[1], data[2], Convert.ToDateTime(data[3])); Student s7 = new Student(Convert.ToInt32(data[0]), data[1], data[2], Convert.ToDateTime(data[3])); studentList2.Add(s6); studentList2.Add(s7); } DisplayOutput(studentList2);