csharp:Compare two DataTables to rows in one but not the other

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239

/// <summary> /// 账面数据 Accounting /// </summary> /// <returns></returns> DataTable setDataAccounting() {     DataTable dt = new DataTable();     dt.Columns.Add("id", typeof(int));     dt.Columns.Add("empno", typeof(string));     dt.Columns.Add("empname", typeof(string));     dt.Columns.Add("sex", typeof(bool));     dt.Columns.Add("wage", typeof(decimal));     dt.Columns.Add("birthday", typeof(DateTime));     dt.Rows.Add(1, "L0001", "涂聚文",false,4500,"1970-03-04");     dt.Rows.Add(2, "L0002", "刘杰", false, 4300, "1972-04-04");     dt.Rows.Add(3, "L0003", "宋承宪", false, 4500, "1974-04-04");     dt.Rows.Add(4, "L0005", "宁夏", false, 4500, "1973-04-04");     dt.Rows.Add(6, "L0009", "江东", true, 5500, "1975-04-04");     dt.Rows.Add(6, "L0010", "李燕云", true, 9500, "1976-04-04");     dt.Rows.Add(7, "L0020", "赵雅芝", false, 14500, "1977-04-04");       return dt; } /// <summary> /// 盘点数据 Inventory /// </summary> /// <returns></returns> DataTable setDataInventory() {     DataTable dt = new DataTable();     dt.Columns.Add("id", typeof(int));     dt.Columns.Add("empno", typeof(string));     dt.Columns.Add("empname", typeof(string));     dt.Columns.Add("sex", typeof(bool));     dt.Columns.Add("wage", typeof(decimal));     dt.Columns.Add("birthday", typeof(DateTime));     dt.Rows.Add(10, "L0001", "涂聚文", false, 4500, "1970-03-04");     dt.Rows.Add(11, "L0002", "刘杰", false, 4300, "1972-04-04");     dt.Rows.Add(12, "L0009", "江东", true, 5500, "1973-04-04");     dt.Rows.Add(13, "L0010", "李燕云", true, 9500, "1974-04-04");     dt.Rows.Add(14, "L0020", "赵雅芝", false, 14500, "1975-04-04");     dt.Rows.Add(15, "L0032", "徐若萱", false, 4300, "1976-04-04");     dt.Rows.Add(16, "L0056", "保芝林", true, 4200, "1977-04-04");     dt.Rows.Add(17, "L0042", "何燕华", false, 4100, "1978-04-04");     dt.Rows.Add(18, "L0052", "黄花菜", false, 4400, "1979-04-04");     dt.Rows.Add(19, "L0012", "艾薇儿", true, 5500, "1982-04-04");     dt.Rows.Add(20, "L0018", "傅艺伟", false, 6500, "1932-04-04");     dt.Rows.Add(21, "L0028", "李世民", false, 9500, "1992-04-04");     return dt; }     /// <summary> /// /// </summary> public Form1() {     InitializeComponent(); } /// <summary> /// /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void Form1_Load(object sender, EventArgs e) {     this.dataGridViewAccounting.DataSource = setDataAccounting();       this.dataGridViewInventory.DataSource = setDataInventory();       } /// <summary> /// 比结果 /// /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void button1_Click(object sender, EventArgs e) {       try     {         DataTable datadiff1 = new DataTable();         DataTable datadiff2 = new DataTable();         DataTable dataOverage = new DataTable();//盘盈         DataTable dataInventoryLoss = new DataTable();//盘亏           DataTable datatable1 = setDataAccounting();         DataTable datatable2 = setDataInventory();             #region         //var qry1 = datatable1.AsEnumerable().Select(a => new { MobileNo = a["empno"].ToString() });         //var qry2 = datatable2.AsEnumerable().Select(b => new { MobileNo = b["empno"].ToString() });         //var exceptAB = qry1.Except(qry2);         ////         //DataTable dtMisMatch = (from a in datatable1.AsEnumerable()         //                        join ab in exceptAB on a["empno"].ToString() equals ab.MobileNo         //                        select a).CopyToDataTable();           ////detect row deletes - a row is in datatable1 except missing from datatable2         //var exceptAB1 = qry1.Except(qry2);         // dataInventoryLoss= (from a in datatable1.AsEnumerable()         //               join ab in exceptAB1 on a["empno"].ToString() equals ab.MobileNo         //               select a).CopyToDataTable();         ////detect row inserts - a row is in datatable2 except missing from datatable1         //var exceptAB2 = qry2.Except(qry1);         // dataOverage = (from a in datatable2.AsEnumerable()         //                     join ab in exceptAB2 on a["empno"].ToString() equals ab.MobileNo         //                     select a).CopyToDataTable();           #endregion          //CompareDataTable(setDataAccounting(), setDataInventory(), "empno","id", out dataOverage, out datadiff1, out datadiff2, out dataInventoryLoss);         CompareLinQDataTable(setDataAccounting(), setDataInventory(), "empno", out dataOverage, out dataInventoryLoss);           this.dataGridViewOverage.DataSource =dataOverage;         this.dataGridViewInventoryLoss.DataSource = dataInventoryLoss;         this.dataGridViewAdd.DataSource =datadiff1 ;         this.dataGridViewDel.DataSource = datadiff2;     }     catch (Exception ex)     {         ex.Message.ToString();     }     }     /// <summary> /// 比较两个DataTableCompare数据（结构相同） /// 涂聚文 /// http://www.codeproject.com/Tips/344792/Compare-two-datatable-using-LINQ-Query /// </summary> /// <param name="datatable1"></param> /// <param name="datatable2"></param> /// <param name="keyField"></param> /// <param name="dataOverage"></param> /// <param name="dataInventoryLoss"></param> public static void CompareLinQDataTable(DataTable datatable1, DataTable datatable2, string keyField,out DataTable dataOverage,out DataTable dataInventoryLoss) {     var qry1 = datatable1.AsEnumerable().Select(a => new { IdNo = a[keyField].ToString() });     var qry2 = datatable2.AsEnumerable().Select(b => new { IdNo = b[keyField].ToString() });     //detect row deletes - a row is in datatable1 except missing from datatable2     var exceptAB1 = qry1.Except(qry2);     dataInventoryLoss = (from a in datatable1.AsEnumerable()                          join ab in exceptAB1 on a[keyField].ToString() equals ab.IdNo                          select a).CopyToDataTable();     //detect row inserts - a row is in datatable2 except missing from datatable1     var exceptAB2 = qry2.Except(qry1);     dataOverage = (from a in datatable2.AsEnumerable()                    join ab in exceptAB2 on a[keyField].ToString() equals ab.IdNo                    select a).CopyToDataTable();   }   /// <summary> /// 比较两个DataTableCompare数据（结构相同） /// 来源于:http://www.cnblogs.com/houlinbo/archive/2010/02/10/1667189.html /// </summary> /// <param name="dt1">来自数据库的DataTable</param> /// <param name="dt2">来自文件的DataTable</param> /// <param name="keyField">要比较的关键字段名</param> /// <param name="keyid">不需要比较的字段名id</param> /// <param name="dtRetAdd">新增数据（dt2中的数据）</param> /// <param name="dtRetDif1">不同的数据（数据库中的数据）</param> /// <param name="dtRetDif2">不同的数据（dt2中的数据,修改过的）</param> /// <param name="dtRetDel">删除的数据（dt2中的数据）</param> public static void CompareDataTable(DataTable dt1, DataTable dt2, string keyField,string keyid, out DataTable dtRetAdd, out DataTable dtRetDif1, out DataTable dtRetDif2,out DataTable dtRetDel) {     //为三个表拷贝表结构     dtRetDel = dt1.Clone();     dtRetAdd = dtRetDel.Clone();     dtRetDif1 = dtRetDel.Clone();     dtRetDif2 = dtRetDel.Clone();       int colCount = dt1.Columns.Count;       DataView dv1 = dt1.DefaultView;     DataView dv2 = dt2.DefaultView;       //先以第一个表为参照，看第二个表是修改了还是删除了     foreach (DataRowView dr1 in dv1)     {         dv2.RowFilter = keyField + " = '" + dr1[keyField].ToString() + "'";         if (dv2.Count > 0)         {             if (!CompareUpdate(dr1, dv2[0]))//比较是否有不同的             {                 dtRetDif1.Rows.Add(dr1.Row.ItemArray);//修改前                 dtRetDif2.Rows.Add(dv2[0].Row.ItemArray);//修改后                 dtRetDif2.Rows[dtRetDif2.Rows.Count - 1][keyid] = dr1.Row[keyid];//将ID赋给来自文件的表，因为它的ID全部==0                 continue;             }         }         else         {             //已经被删除的             dtRetDel.Rows.Add(dr1.Row.ItemArray);         }     }       //以第一个表为参照，看记录是否是新增的     dv2.RowFilter = "";//清空条件     foreach (DataRowView dr2 in dv2)     {         dv1.RowFilter = keyField + " = '" + dr2[keyField].ToString() + "'";         if (dv1.Count == 0)         {             //新增的             dtRetAdd.Rows.Add(dr2.Row.ItemArray);         }     } }   /// <summary> /// /// </summary> /// <param name="dr1"></param> /// <param name="dr2"></param> /// <returns></returns> private static bool CompareUpdate(DataRowView dr1, DataRowView dr2) {     //行里只要有一项不一样，整个行就不一样,无需比较其它     object val1;     object val2;     for (int i = 1; i < dr1.Row.ItemArray.Length; i++)     {         val1 = dr1[i];         val2 = dr2[i];         if (!val1.Equals(val2))         {             return false;         }     }     return true; }

　　

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557

/// <summary>     ///datatable relational operators     ///20150825     ///Geovin Du     ///http://weblogs.sqlteam.com/davidm/archive/2004/01/21/753.aspx     /// </summary>     public class SQLOps     {         /// <summary>         ///         /// </summary>         public SQLOps()         {               //               // TODO: Add constructor logic here               //           }         /// <summary>         ///         /// </summary>         /// <param name="First"></param>         /// <param name="Second"></param>         /// <param name="FJC"></param>         /// <param name="SJC"></param>         /// <returns></returns>         public static DataTable Join(DataTable First, DataTable Second, DataColumn[] FJC, DataColumn[] SJC)         {               //Create Empty Table               DataTable table = new DataTable("Join");               // Use a DataSet to leverage DataRelation               using (DataSet ds = new DataSet())             {                   //Add Copy of Tables                   ds.Tables.AddRange(new DataTable[] { First.Copy(), Second.Copy() });                 //Identify Joining Columns from First                   DataColumn[] parentcolumns = new DataColumn[FJC.Length];                       for (int intLoop = 0; intLoop < parentcolumns.Length; intLoop++)                 {                       parentcolumns[intLoop] = ds.Tables[0].Columns[FJC[intLoop].ColumnName];                   }                   //Identify Joining Columns from Second                   DataColumn[] childcolumns = new DataColumn[SJC.Length];                       for (int intLoop = 0; intLoop < childcolumns.Length; intLoop++)                 {                       childcolumns[intLoop] = ds.Tables[1].Columns[SJC[intLoop].ColumnName];                   }                 //Create DataRelation                   DataRelation r = new DataRelation(string.Empty, parentcolumns, childcolumns, false);                   ds.Relations.Add(r);                 //Create Columns for JOIN table                   for (int intLoop = 0; intLoop < First.Columns.Count; intLoop++)                 {                       table.Columns.Add(First.Columns[intLoop].ColumnName, First.Columns[intLoop].DataType);                   }                 for (int intLoop = 0; intLoop < Second.Columns.Count; intLoop++)                 {                       //Beware Duplicates                       if (!table.Columns.Contains(Second.Columns[intLoop].ColumnName))                           table.Columns.Add(Second.Columns[intLoop].ColumnName, Second.Columns[intLoop].DataType);                       else                           table.Columns.Add(Second.Columns[intLoop].ColumnName + "_Second", Second.Columns[intLoop].DataType);                   }                 //Loop through First table                   table.BeginLoadData();                       foreach (DataRow firstrow in ds.Tables[0].Rows)                 {                       //Get "joined" rows                       DataRow[] childrows = firstrow.GetChildRows(r);                           if (childrows != null && childrows.Length > 0)                     {                           object[] parentarray = firstrow.ItemArray;                               foreach (DataRow secondrow in childrows)                         {                               object[] secondarray = secondrow.ItemArray;                               object[] joinarray = new object[parentarray.Length + secondarray.Length];                               Array.Copy(parentarray, 0, joinarray, 0, parentarray.Length);                               Array.Copy(secondarray, 0, joinarray, parentarray.Length, secondarray.Length);                               table.LoadDataRow(joinarray, true);                         }                       }                   }                 table.EndLoadData();               }             return table;           }         /// <summary>         ///         /// </summary>         /// <param name="First"></param>         /// <param name="Second"></param>         /// <param name="FJC"></param>         /// <param name="SJC"></param>         /// <returns></returns>         public static DataTable Join(DataTable First, DataTable Second, DataColumn FJC, DataColumn SJC)         {               return Join(First, Second, new DataColumn[] { FJC }, new DataColumn[] { SJC });           }         /// <summary>         ///         /// </summary>         /// <param name="First"></param>         /// <param name="Second"></param>         /// <param name="FJC"></param>         /// <param name="SJC"></param>         /// <returns></returns>         public static DataTable Join(DataTable First, DataTable Second, string FJC, string SJC)         {               return Join(First, Second, new DataColumn[] { First.Columns[FJC] }, new DataColumn[] { First.Columns[SJC] });           }         /// <summary>         ///         /// </summary>         /// <param name="First"></param>         /// <param name="Second"></param>         /// <returns></returns>         public static DataTable Intersect(DataTable First, DataTable Second)         {               //Get reference to Columns in First               DataColumn[] firstcolumns = new DataColumn[First.Columns.Count];               for (int i = 0; i < firstcolumns.Length; i++)             {                   firstcolumns[i] = First.Columns[i];               }               //Get reference to Columns in Second               DataColumn[] secondcolumns = new DataColumn[Second.Columns.Count];               for (int i = 0; i < secondcolumns.Length; i++)             {                   secondcolumns[i] = Second.Columns[i];               }               //JOIN ON all columns               DataTable table = SQLOps.Join(First, Second, firstcolumns, secondcolumns);               table.TableName = "Intersect";               return table;           }             /// <summary>         ///         /// </summary>         /// <param name="Values"></param>         /// <param name="OtherValues"></param>         /// <returns></returns>         public static bool RowEqual(object[] Values, object[] OtherValues)         {               if (Values == null)                   return false;                   for (int i = 0; i < Values.Length; i++)             {                   if (!Values[i].Equals(OtherValues[i]))                       return false;               }               return true;           }                 /// <summary>         ///         /// </summary>         /// <param name="Table"></param>         /// <param name="Columns"></param>         /// <returns></returns>         public static DataTable Distinct(DataTable Table, DataColumn[] Columns)         {               //Empty table               DataTable table = new DataTable("Distinct");               //Sort variable               string sort = string.Empty;                   //Add Columns & Build Sort expression               for (int i = 0; i < Columns.Length; i++)             {                   table.Columns.Add(Columns[i].ColumnName, Columns[i].DataType);                   sort += Columns[i].ColumnName + ",";               }               //Select all rows and sort               DataRow[] sortedrows = Table.Select(string.Empty, sort.Substring(0, sort.Length - 1));                   object[] currentrow = null;               object[] previousrow = null;                   table.BeginLoadData();               foreach (DataRow row in sortedrows)             {                   //Current row                   currentrow = new object[Columns.Length];                   for (int i = 0; i < Columns.Length; i++)                 {                       currentrow[i] = row[Columns[i].ColumnName];                   }                       //Match Current row to previous row                   if (!SQLOps.RowEqual(previousrow, currentrow))                       table.LoadDataRow(currentrow, true);                       //Previous row                   previousrow = new object[Columns.Length];                   for (int i = 0; i < Columns.Length; i++)                 {                       previousrow[i] = row[Columns[i].ColumnName];                   }                   }               table.EndLoadData();               return table;               }             /// <summary>         ///         /// </summary>         /// <param name="Table"></param>         /// <param name="Column"></param>         /// <returns></returns>         public static DataTable Distinct(DataTable Table, DataColumn Column)         {               return Distinct(Table, new DataColumn[] { Column });           }         /// <summary>         ///         /// </summary>         /// <param name="Table"></param>         /// <param name="Column"></param>         /// <returns></returns>         public static DataTable Distinct(DataTable Table, string Column)         {               return Distinct(Table, Table.Columns[Column]);           }         /// <summary>         ///         /// </summary>         /// <param name="Table"></param>         /// <param name="Columns"></param>         /// <returns></returns>         public static DataTable Distinct(DataTable Table, params string[] Columns)         {               DataColumn[] columns = new DataColumn[Columns.Length];               for (int i = 0; i < Columns.Length; i++)             {                   columns[i] = Table.Columns[Columns[i]];                   }               return Distinct(Table, columns);           }         /// <summary>         ///         /// </summary>         /// <param name="Table"></param>         /// <returns></returns>         public static DataTable Distinct(DataTable Table)         {               DataColumn[] columns = new DataColumn[Table.Columns.Count];               for (int i = 0; i < Table.Columns.Count; i++)             {                   columns[i] = Table.Columns[i];                   }               return Distinct(Table, columns);           }           /// <summary>         ///         /// </summary>         /// <param name="First"></param>         /// <param name="Second"></param>         /// <returns></returns>         public static DataTable Union(DataTable First, DataTable Second)         {             //Result table             DataTable table = new DataTable("Union");             //Build new columns             DataColumn[] newcolumns = new DataColumn[First.Columns.Count];             for (int i = 0; i < First.Columns.Count; i++)             {                 newcolumns[i] = new DataColumn(First.Columns[i].ColumnName, First.Columns[i].DataType);             }             //add new columns to result table             table.Columns.AddRange(newcolumns);             table.BeginLoadData();             //Load data from first table             foreach (DataRow row in First.Rows)             {                 table.LoadDataRow(row.ItemArray, true);             }             //Load data from second table             foreach (DataRow row in Second.Rows)             {                 table.LoadDataRow(row.ItemArray, true);             }             table.EndLoadData();             return table;         }           /// <summary>         /// 多个 结构相同的DataTable合并         /// </summary>         /// <returns></returns>         public static DataTable GetAllEntrysDataTable(List<DataTable> GetEntrysDataTable)         {             DataTable newDataTable = GetEntrysDataTable[0].Clone();             object[] obj = new object[newDataTable.Columns.Count];             for (int i = 0; i < GetEntrysDataTable.Count; i++)//entryGroups.GetEntryGroupCount()             {                 for (int j = 0; j < GetEntrysDataTable[i].Rows.Count; j++)                 {                     GetEntrysDataTable[i].Rows[j].ItemArray.CopyTo(obj, 0);                     newDataTable.Rows.Add(obj);                 }             }             return newDataTable;         }         /// <summary>         /// 结构不同         /// </summary>         /// <param name="dt1"></param>         /// <param name="dt2"></param>         /// <param name="DTName"></param>         /// <returns></returns>         public static DataTable UnitesDataTable(DataTable dt1, DataTable dt2, string DTName)         {             DataTable dt3 = dt1.Clone();             for (int i = 0; i < dt2.Columns.Count; i++)             {                 dt3.Columns.Add(dt2.Columns[i].ColumnName);             }             object[] obj = new object[dt3.Columns.Count];               for (int i = 0; i < dt1.Rows.Count; i++)             {                 dt1.Rows[i].ItemArray.CopyTo(obj, 0);                 dt3.Rows.Add(obj);             }               if (dt1.Rows.Count >= dt2.Rows.Count)             {                 for (int i = 0; i < dt2.Rows.Count; i++)                 {                     for (int j = 0; j < dt2.Columns.Count; j++)                     {                         dt3.Rows[i][j + dt1.Columns.Count] = dt2.Rows[i][j].ToString();                     }                 }             }             else             {                 DataRow dr3;                 for (int i = 0; i < dt2.Rows.Count - dt1.Rows.Count; i++)                 {                     dr3 = dt3.NewRow();                     dt3.Rows.Add(dr3);                 }                 for (int i = 0; i < dt2.Rows.Count; i++)                 {                     for (int j = 0; j < dt2.Columns.Count; j++)                     {                         dt3.Rows[i][j + dt1.Columns.Count] = dt2.Rows[i][j].ToString();                     }                 }             }             dt3.TableName = DTName; //设置DT的名字             return dt3;         }         /// <summary>         /// 结构不同         /// </summary>         /// <param name="dt1"></param>         /// <param name="dt2"></param>         /// <returns></returns>         public static DataTable UnitesDataTable(DataTable dt1, DataTable dt2)         {             DataTable dt3 = dt1.Clone();             for (int i = 0; i < dt2.Columns.Count; i++)             {                 dt3.Columns.Add(dt2.Columns[i].ColumnName);             }             object[] obj = new object[dt3.Columns.Count];               for (int i = 0; i < dt1.Rows.Count; i++)             {                 dt1.Rows[i].ItemArray.CopyTo(obj, 0);                 dt3.Rows.Add(obj);             }               if (dt1.Rows.Count >= dt2.Rows.Count)             {                 for (int i = 0; i < dt2.Rows.Count; i++)                 {                     for (int j = 0; j < dt2.Columns.Count; j++)                     {                         dt3.Rows[i][j + dt1.Columns.Count] = dt2.Rows[i][j].ToString();                     }                 }             }             else             {                 DataRow dr3;                 for (int i = 0; i < dt2.Rows.Count - dt1.Rows.Count; i++)                 {                     dr3 = dt3.NewRow();                     dt3.Rows.Add(dr3);                 }                 for (int i = 0; i < dt2.Rows.Count; i++)                 {                     for (int j = 0; j < dt2.Columns.Count; j++)                     {                         dt3.Rows[i][j + dt1.Columns.Count] = dt2.Rows[i][j].ToString();                     }                 }             }             //dt3.TableName = DTName; //设置DT的名字             return dt3;         }     }