In this article I will explain with an example, how to populate DataGridView using Generic List collection in Windows Forms (WinForms) Application using C# and VB.Net.
This article will make use of SqlDataReader to populate the data from SQL Server database in C# and VB.Net.
 
 

Database

Here I am making use of Microsoft’s Northwind Database. You can download it from here.
Download and install Northwind Database
 
 

Form Design

The following Form consists of:
DataGridView – For displaying data.
Populate DataGridView using Generic List Collection in C# and VB.Net
 
 

Namespaces

You will need to import the following namespaces.
C#
using System.Data.SqlClient;
using System.Configuration;
 
VB.Net
Imports System.Data.SqlClient
Imports System.Configuration
 
 

Public Class

The public class consists of following properties.
C#
public class Customer
{
    public string CustomerId { get; set; }
    public string Name { get; set; }
    public string Country { get; set; }
}
 
VB.Net
Public Class Customer
    Public Property CustomerId As String
    Public Property Name As String
    Public Property Country As String
End Class
 
 

Populating DataGridView using Generic List Collection in C# and VB.Net

Inside the Form Load event handler, the BindGrid method is called.
Inside the BindGrid method, first the connection string is read from App.Config file.
Note: For more details on how to read connection string from App.Config file please refer my article .Net 4.5: Read (Get) Connection String from App.Config file using C# and VB.Net.
 
Then, an object of SqlCommand class is created and the SELECT query is passed to it as parameter and the Generic List collection of Customer class is created.
The connection is opened and an object of SqlDataReader is created and the ExecuteReader function is executed.
Then, a WHILE loop is executed and fetched records are added to the Generic List collection of Customer class object.
Finally, the Generic List collection of Customer class object is assigned to the DataSource property of DataGridView and the DataGridView is populated.
Note: Here Generic List collection is used, but SqlDataReader can be directly used to populate DataSet or DataTable.
 
C#
private void Form1_Load(object sender, EventArgs e)
{
    this.BindGrid();
}
 
private void BindGrid()
{
    string sql = "SELECT CustomerId, ContactName, Country FROM Customers";
    string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand(sql, con))
        {
            List<Customer> customers = new List<Customer>();
            con.Open();
            using (SqlDataReader sdr = cmd.ExecuteReader())
            {
                while (sdr.Read())
                {
                    customers.Add(new Customer
                    {
                        CustomerId = sdr["CustomerId"].ToString(),
                        Name = sdr["ContactName"].ToString(),
                        Country = sdr["Country"].ToString()
                    });
                }
            }
            con.Close();
            dgvCustomers.DataSource = customers;
        }
    }
}
 
VB.Net
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.Load
    Me.BindGrid()
End Sub
 
Private Sub BindGrid()
    Dim sql As String = "SELECT CustomerId, ContactName, Country FROM Customers"
    Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
    Using con As SqlConnection = New SqlConnection(constr)
        Using cmd As SqlCommand = New SqlCommand(sql, con)
            Dim customers As List(Of Customer) = New List(Of Customer)()
            con.Open()
            Using sdr As SqlDataReader = cmd.ExecuteReader()
                While sdr.Read()
                    customers.Add(New Customer With {
                        .CustomerId = sdr("CustomerId").ToString(),
                        .Name = sdr("ContactName").ToString(),
                        .Country = sdr("Country").ToString()
                    })
                End While
            End Using
            con.Close()
            dgvCustomers.DataSource = customers
        End Using
    End Using
End Sub
 
 

Screenshot

Populate DataGridView using Generic List Collection in C# and VB.Net
 
 

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