In this article we will convert an DataTable Object into List Object. and learn c# datatable, c# list and generic collection in c#. Sometimes we will face a situation in mixed mode code standard like Entity Framework (EF) with Ado.net. For such code standards we needs to convert DataTable object into List Object and vice versa.
Step 1: Open Visual Studio. Create Console Application. Import required namesapces. System.Collections for ArrayList, System.Collections.Generic for List, System for Console and System.Data for DataTable.
using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
Step 2: Create an DataTable with Columns related to Student and populate DataTable with some dummy student data.
DataTable dt = new DataTable("Students");
//Creates DataTable Object
DataTable dt = new DataTable("Students");
//Create Static Columns for DataTable
dt.Columns.Add("StudentId", Type.GetType("System.Int32"));
dt.Columns.Add("RollNo", Type.GetType("System.Int32"));
dt.Columns.Add("ClassName");
dt.Columns.Add("Sectionname");
dt.Columns.Add("SessionName");
dt.Columns.Add("StudentName");
ArrayList n = new ArrayList();
n.Add("Jack");
n.Add("Maria");
n.Add("Wiliam");
n.Add("Rock");
n.Add("Marina");
n.Add("Harish");
n.Add("Jhon");
n.Add("Raidu");
int i = 1;
foreach (string s in n)
{
dt.Rows.Add(i, i + 1000, "10th", "C", "2019-2020", s);
i++;
}
//Retrive Data From DataTable
foreach (DataRow r in dt.Rows)
{
Console.WriteLine("=========================================");
foreach (DataColumn c in dt.Columns)
{
Console.WriteLine($"{c.ToString()}: {r[c.ToString()]}");
}
}
Step 3: Create an Data Transfer Object Class for Student and map its properties with Student DataTable.
public class StudentDTO
{
public int StudentId { get; set; }
public int RollNo { get; set; }
public string ClassName { get; set; }
public string Sectionname { get; set; }
public string SessionName { get; set; }
public string StudentName { get; set; }
}
Step 4: Create List Object for StudetDTO and insert data from DataTable.
// Creating Student DTO Object
List stu = new List();
foreach (DataRow r in dt.Rows)
{
stu.Add(new StudentDTO()
{
StudentId = Convert.ToInt32(r["StudentId"]),
RollNo = Convert.ToInt32(r["RollNo"]),
ClassName = Convert.ToString(r["ClassName"]),
Sectionname = Convert.ToString(r["Sectionname"]),
SessionName = Convert.ToString(r["SessionName"]),
StudentName = Convert.ToString(r["StudentName"]),
});
}
Step 5: Retrieve Student data from List Generic object.
foreach (StudentDTO s in stu)
{
Console.WriteLine($"StudentId: {s.StudentId} StudentName: {s.StudentName}");
}
The overall program will be as follows.
using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
namespace ConsoleApplication
{
public class StudentDTO
{
public int StudentId { get; set; }
public int RollNo { get; set; }
public string ClassName { get; set; }
public string Sectionname { get; set; }
public string SessionName { get; set; }
public string StudentName { get; set; }
}
class Program
{
static void Main(string[] args)
{
//Creates DataTable Object
DataTable dt = new DataTable("Students");
//Create Static Columns for DataTable
dt.Columns.Add("StudentId", Type.GetType("System.Int32"));
dt.Columns.Add("RollNo", Type.GetType("System.Int32"));
dt.Columns.Add("ClassName");
dt.Columns.Add("Sectionname");
dt.Columns.Add("SessionName");
dt.Columns.Add("StudentName");
ArrayList n = new ArrayList();
n.Add("Jack");
n.Add("Maria");
n.Add("Wiliam");
n.Add("Rock");
n.Add("Marina");
n.Add("Harish");
n.Add("Jhon");
n.Add("Raidu");
int i = 1;
foreach (string s in n)
{
dt.Rows.Add(i, i + 1000, "10th", "C", "2019-2020", s);
i++;
}
//Retrive Data From DataTable
foreach (DataRow r in dt.Rows)
{
Console.WriteLine("=========================================");
foreach (DataColumn c in dt.Columns)
{
Console.WriteLine($"{c.ToString()}: {r[c.ToString()]}");
}
}
// Creating Student DTO Object
List stu = new List();
foreach (DataRow r in dt.Rows)
{
stu.Add(new StudentDTO()
{
StudentId = Convert.ToInt32(r["StudentId"]),
RollNo = Convert.ToInt32(r["RollNo"]),
ClassName = Convert.ToString(r["ClassName"]),
Sectionname = Convert.ToString(r["Sectionname"]),
SessionName = Convert.ToString(r["SessionName"]),
StudentName = Convert.ToString(r["StudentName"]),
});
}
Console.WriteLine("=========List Generic Data:==============");
//Retrive Data From List Generic
foreach (StudentDTO s in stu)
{
Console.WriteLine($"StudentId: {s.StudentId} StudentName: {s.StudentName}");
}
Console.ReadKey();
}
}
}
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