DataTable dt_Princ = new DataTable();
            DataSourseTo dts_Princ = new DataSourseTo();
            dt_Princ = dts_Princ.GetData("SELECT  k_princ, n_princ_s,IncCurrNumContract, k_otdel " +
                                         " FROM dbo.princ ");
            dGVcmb.DataSource = dt_Princ;
            DataGridViewComboBoxColumn cmbCol = new DataGridViewComboBoxColumn();
            cmbCol.DataPropertyName  = "IncCurrNumContract";
            cmbCol.DataSource = dt_Princ.Columns[2];
            cmbCol .ValueMember =dt_Princ.Columns[2].ToString ();
            cmbCol .DisplayMember =dt_Princ.Columns[2].ToString ();
            dGVcmb.Columns.Add(cmbCol);