Query the DB
sql="Select uID,cUnit from tblUnit";
Now add a combo column in datagridview and pass datatable
public void AddColumnCombo(DataGridView Grid, string sCaption, DataTable dt, string sDisplayMember, string sValueMember)
{
DataGridViewComboBoxColumn GColumn = new DataGridViewComboBoxColumn
{
HeaderText = sCaption,
DataSource = dt,
DisplayMember = sDisplayMember,
ValueMember = sValueMember
};
Grid.Columns.Add(GColumn);
}
now asign the value to set required data for eg set 2 to display B
DataGridView[0,0].Value = Convert.ToString(datarow["UId"]) == "" ? null : (object)Convert.ToInt32(datarow["UId"]);