赋值：

第一种方法：

控件名称为：cmbXb

cmbXb.Items.Add("男");
    cmbXb.Items.Add("女");
    cmbXb.SelectedIndex = 0;

第二种方法：

控件名称为：cbxGuoji

string sql = "select id,mc from ZDYLX where fl = 'gj' and zt = '正常'";
    List<NationalityInfo> Mylist = new List<NationalityInfo>();
    NationalityInfo nationality = null;

nationality = new NationalityInfo();
    nationality.id = Convert.ToInt32(0);
    nationality.mc = "";

Mylist.Add(nationality);

using (DataSet Myds = DbHelperSQL.Query(sql))
    {
           using (DataTable Mytable = Myds.Tables[0])
           {
                  for (int i = 0; i < Mytable.Rows.Count; i++)
                  {
                        nationality = new NationalityInfo();
                        nationality.id = Convert.ToInt32(Mytable.Rows[i][0].ToString());
                        nationality.mc = Mytable.Rows[i][1].ToString();
                        Mylist.Add(nationality);
                   }
             }
      }
      //清除原有数据
      cbxGuoji.DataSource = null;

//绑定新数据
      cbxGuoji.DataSource = Mylist;
      cbxGuoji.DisplayMember = "mc";
      cbxGuoji.ValueMember = "id";

使用：

第一种方法：  cbxGuoji

string nation = Convert.ToString(myTable.Rows[0][11]);
    cbxGuoji.Text = nation;

第二种方法：   cbxMoney

string npjsr = Convert.ToString(myTable.Rows[0][23]);
     for (int i = 0; i < cbxMoney.Items.Count; i++)
     {
             if (cbxMoney.GetItemText(cbxMoney.Items[i]) == npjsr)
              {
                     cbxMoney.SelectedItem = cbxMoney.Items[i];
               }
     }