Dynamically generate CSV file from Database by retaining delimited character (comma) using C# and VB.Net in ASP.Net

Protected Sub ExportCSV(sender As Object, e As EventArgs)
    Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
    Using con As New SqlConnection(constr)
        Using cmd As New SqlCommand("SELECT 'a,b,c,v'column1, 'ass,ff,fff ,kkkl,f,'column2 FROM Customers")
            Using sda As New SqlDataAdapter()
                cmd.Connection = con
                sda.SelectCommand = cmd
                Using dt As New DataTable()
                    sda.Fill(dt)
 
                    'Build the CSV file data as a Comma separated string.
                    Dim csv As String = String.Empty
 
                    For Each column As DataColumn In dt.Columns
                        'Add the Header row for CSV file.
                        csv += column.ColumnName + ","c
                    Next
 
                    'Add new line.
                    csv += vbCr & vbLf
 
                    For Each row As DataRow In dt.Rows
                        For Each column As DataColumn In dt.Columns
                            'Add the Data rows.
                            csv += row(column.ColumnName).ToString().Replace(",", ";") + ","c
                        Next
 
                        'Add new line.
                        csv += vbCr & vbLf
                    Next
 
                    'Download the CSV file.
                    Response.Clear()
                    Response.Buffer = True
                    Response.AddHeader("content-disposition", "attachment;filename=SqlExport.csv")
                    Response.Charset = ""
                    Response.ContentType = "application/text"
                    Response.Output.Write(csv)
                    Response.Flush()
                    Response.End()
                End Using
            End Using
        End Using
    End Using
End Sub