Convert DataTable to List in C#

Introduction:

When working with data in C#, it is common to use a DataTable object to hold the data. A DataTable is a powerful data structure that allows you to manipulate and analyze data in many different ways. However, sometimes you may need to convert a DataTable into a list of objects for further processing. In this article, we will dive deep into how to convert a DataTable to a list in C#.

What is a DataTable?

A DataTable is a class in C# that is used to represent a table of data in memory. It is similar to a table in a Database, with rows and columns. A DataTable can be populated with data from various sources such as a Database, XML file or even a CSV file. Once the data is loaded into a DataTable, it can be manipulated, sorted, filtered or displayed in various ways.

What is a List?

A List is a collection of items of the same data type. It can be considered as an Array with dynamic size. A List provides various functionalities such as adding or removing items, sorting, filtering or searching for items.

Why convert a DataTable to a List?

While a DataTable is a powerful data structure, sometimes it is not the most convenient format for further processing. For example, if you want to perform LINQ queries on the data or use a third-party library that requires a list of objects, it may be more efficient to convert the DataTable to a list. Additionally, a list may be easier to work with if you are working with a smaller subset of data or if you need to manipulate the data in a more specialized way.

Steps to Convert DataTable to List in C#

The following are the steps to convert a DataTable to a list in C#:

Create a class that represents the data in each row of the DataTable. This class should have attributes that correspond to the columns in the DataTable.
Create a new List object that will hold the converted data.
Loop through each row in the DataTable.
Create a new object of the class created in step 1.
Populate the properties of the object with the values from the current row in the DataTable.
Add the object to the List created in step 2.
Return the List.

Let's take an example to understand how to convert a DataTable to a List in C#.

Consider a DataTable named "Employee" with columns "Id", "Name" and "Salary". We want to convert this DataTable to a List of "Employee" objects.

C# Code:

DataTable dt = new DataTable();
dt.Columns.Add("Id", typeof(int));
dt.Columns.Add("Name", typeof(string));
dt.Columns.Add("Salary", typeof(int));
dt.Rows.Add(1, "John", 5000);
dt.Rows.Add(2, "Mary", 6000);
dt.Rows.Add(3, "Jane", 7000);

To convert this DataTable to a List of Employee objects, we will create a class named "Employee" with properties "Id", "Name" and "Salary".

C# Code:

public class Employee
{
    public int Id { get; set; }
    public string Name { get; set; }
    public int Salary { get; set; }
}

Now, we will iterate through the rows of the DataTable and create a new Employee object for each row. This object is then added to the List.

C# Code:

List<Employee> employees = new List<Employee>();
foreach (DataRow row in dt.Rows)
{
    Employee employee = new Employee();
    employee.Id = Convert.ToInt32(row["Id"]);
    employee.Name = row["Name"].ToString();
    employee.Salary = Convert.ToInt32(row["Salary"]);
    employees.Add(employee);
}

In the above code, we first created an empty List of Employee objects named "employees". Then we used a foreach loop to iterate through each row of the DataTable "dt". For each row, we created a new Employee object named "employee". We then assigned the values of the "Id", "Name" and "Salary" columns of the row to the properties of the Employee object. Finally, we added this object to the List "employees".

We can now use this List to manipulate the data or display it in a different format.

Conclusion:

Converting a DataTable to a List can be useful in various scenarios where we want to manipulate the data or display it in a different format. It involves iterating through the rows of the DataTable and creating a new object for each row that represents the data in the row. This object is then added to the List. In this article, we discussed how to convert a DataTable to a List in C# using an example.

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