data Grid View Combo Box query

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VB

I have a datagridview having 2 buttons ADD and VIEW.
On click of VIEW button, it fetches the data from .csv file.
Now I want to change a column into combobox at run time means if I click on ADD button it will show a new row and on 2 columns it shows the combobox which is having some dropdown values in it(user selects the value from dropdown).

The below code is able to read a file into datagrid but what should I do to add a new row with combobox.

Public Class frmGrid
    Dim dt As DataTable = New DataTable
    Dim ds As DataSet = New DataSet
    Dim dv As DataView = New DataView
    ' Dim dgv2Cb As New DataGridViewComboBoxCell
    Dim ColumnCB As New DataGridViewComboBoxColumn
    Dim ChkBox As New DataGridViewCheckBoxColumn
    
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    Dim fName As String = ""
    Dim strline As String
    Dim charArray As Char = ","
    Dim strArray() As String

    OpenFileDialog1.FilterIndex = 2
    OpenFileDialog1.RestoreDirectory = True

    If (OpenFileDialog1.ShowDialog() = Windows.Forms.DialogResult.OK) Then

        fName = OpenFileDialog1.FileName
        Dim aFile As FileStream = New FileStream(fName, FileMode.Open)
        Dim sr As StreamReader = New StreamReader(aFile)

        strline = sr.ReadLine
        strArray = strline.Split(charArray)
        For i As Integer = 0 To strArray.GetUpperBound(0)
            dt.Columns.Add(strArray(i).Trim())
            dt.TableName = "BPSurv"
           
        Next
        Me.grdTest.DataSource = dt
        strline = sr.ReadLine()
        ChkBox.Name = "Select"
        ChkBox.Selected = False
        grdTest.Columns.Add(ChkBox)
        While strline <> Nothing
            strArray = strline.Split(charArray)
            Dim dr As DataRow = dt.NewRow
            'Dim dc As DataColumn
            For i As Integer = 0 To strArray.GetUpperBound(0)
                'Dim dgvc As DataGridViewComboBoxCell
                dr(i) = strArray(i).Trim
            Next
            dt.Rows.Add(dr)
            strline = sr.ReadLine()

        End While

    End If
    
End Sub