Made combobox in dgv

Made by Row in datagridview

foreach (DataGridViewRow drg in this.dgvAppraisalTopic.Rows) {  if (dtScore != null)  {     var col = drg.Cells["Score"] as DataGridViewComboBoxCell;     col.Items.Clear();     col.DataSource = new BindingSource(dtScore, null);     col.DisplayMember = "Score"; //name of column indataTable to display!!     col.ValueMember = "Score";  } }