Whenever I Clicked On The Header Of The Column Then Its Refresh Otherwise Not,How To Solve It?

For iCnt As Integer = 2 To dt.Columns.Count
              If dt.Columns.Count >= 3 Then dt.Columns.RemoveAt(2)
          Next
          If header = "No" Then
              dt.Rows.RemoveAt(0)
          End If
          If checkFile() Then
              gridViewFile.DataSource = dt
              gridViewFile.Refresh()
          Else