SqlConnection con  = new SqlConnection("server=(local);uid=sa;pwd=sa;database=tttttt");
SqlDataAdapter sap = new SqlDataAdapter();
sap.SelectCommand = new SqlCommand("select * from inf_county");
sap.SelectCommand.Connection = con; DataSet ds = new DataSet(); sap.Fill(ds);this.comboBox1.DataSource = ds.Tables[0];
this.comboBox1.DisplayMember = "NAME";
this.comboBox1.ValueMember = "ID";