How to add column in datagridview

Hi there, I have to add some data but without using any database. The data is given by user.

I add columns once but when i do it in second time.
Its not working. Im new in .Net platform.
Here is code

Dim DataGridView1 = New DataGridView
DataGridView1.Columns.Add(“DtNumber”, “No”)
DataGridView1.Columns.Add(“DtName”, ” Name “)
DataGridView1.Columns.Add(“ATX”, “ATX”)
DataGridView1.Columns.Add(“XTP”, “XTP”)
DataGridView1.Columns.Add(“etc”, “etc”)
DataGridView1.Refresh()

Please reply me solution.
Thanks