How to add items in your Combo Box from Database Connection?

Imports System.Data.SqlClient

Public Class Adding_itemsOfComboBox_From_Database
    Dim dr As SqlDataReader

    Private Sub Adding_itemsOfComboBox_From_Database_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Using conn = Opencon()
            Dim cmd As New SqlCommand("Select FIRSTNAME from PATIENT_INFO", conn)
            dr = cmd.ExecuteReader
            While dr.Read

                cboClientName.Items.Add(dr(0))
            End While

        End Using
    End Sub
End Class

Note:
      "Using conn=Opencon()" is a function use as the global declaration of Database Connection. Click here to learn about it.