Set RowHeader in Datagridview

Private Sub dgvPlanner_RowPostPaint(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewRowPostPaintEventArgs) Handles dgvPlanner.RowPostPaint

Me.dgvPlanner.Rows(e.RowIndex).HeaderCell.Value = dgvPlanner.Rows(e.RowIndex).Cells("TimeSlot").Value

End Sub