1 using System;
2 using System.Collections.Generic;
3 using System.Text;
4 using System.Data;
5
6 namespace ConsoleApplication1
7 {
8 /// <summary>
9 /// 在返回的table处大断点查看结果
10 /// </summary>
11 class Program
12 {
13 static void Main(string[] args)
14 {
15 CreatTable();
16 }
17
18 /// <summary>
19 /// 创建两个测试表
20 /// </summary>
21 public static void CreatTable()
22 {
23 //定义数据结构
24 DataTable Ks = new DataTable("客商"); //左表or主表
25 DataColumn dcID = new DataColumn("ID", System.Type.GetType("System.Int32"));
26 DataColumn dcNa = new DataColumn("客商名称", System.Type.GetType("System.String"));
27 Ks.Columns.Add(dcID);
28 Ks.Columns.Add(dcNa);
29
30 DataTable Dj = new DataTable("订单");//右表or子表
31 DataColumn dcID2 = new DataColumn("ID", System.Type.GetType("System.Int32"));
32 DataColumn dcNu = new DataColumn("订单数量", System.Type.GetType("System.Int32"));
33 Dj.Columns.Add(dcID2);
34 Dj.Columns.Add(dcNu);
35
36 //左表数据
37 DataRow KsDt = Ks.NewRow();
38 KsDt["ID"] = 11;
39 KsDt["客商名称"] = "张三";
40 Ks.Rows.Add(KsDt);
41
42 KsDt = Ks.NewRow();
43 KsDt["ID"] = 12;
44 KsDt["客商名称"] = "李四";
45 Ks.Rows.Add(KsDt);
46
47 KsDt = Ks.NewRow();
48 KsDt["ID"] = 13;
49 KsDt["客商名称"] = "王武";
50 Ks.Rows.Add(KsDt);
51
52 KsDt = Ks.NewRow();
53 KsDt["ID"] = 14;
54 KsDt["客商名称"] = "赵柳";
55 Ks.Rows.Add(KsDt);
56
57
58 //右表数据
59 KsDt = Dj.NewRow();
60 KsDt["ID"] = 11;
61 KsDt["订单数量"] = 10;
62 Dj.Rows.Add(KsDt);
63
64 //KsDt = Dj.NewRow();
65 //KsDt["ID"] = 11;
66 //KsDt["订单数量"] = 12;
67 //Dj.Rows.Add(KsDt);
68
69 //KsDt = Dj.NewRow();
70 //KsDt["ID"] = 12;
71 //KsDt["订单数量"] = 16;
72 //Dj.Rows.Add(KsDt);
73
74
75 //KsDt = Dj.NewRow();
76 //KsDt["ID"] = 13;
77 //KsDt["订单数量"] = 30;
78 //Dj.Rows.Add(KsDt);
79
80 KsDt = Dj.NewRow();
81 KsDt["ID"] = 14;
82 KsDt["订单数量"] = 40;
83 Dj.Rows.Add(KsDt);
84
85 KsDt = Dj.NewRow();
86 KsDt["ID"] = 15;
87 KsDt["订单数量"] = 1250;
88 Dj.Rows.Add(KsDt);
89
90 /*********************调用******************************************/
91 //
92 Join(Ks, Dj, new DataColumn[] { Ks.Columns["ID"] }, new DataColumn[] { Dj.Columns["ID"] });
93 //重载1
94 Join(Ks, Dj, Ks.Columns["ID"], Dj.Columns["ID"]);
95 //重载2
96 Join(Ks, Dj, "ID", "ID");
97
98 /*********************调用结束**************************************/
99 }
100
101 /// <summary>
102 /// 建立两内存表的链接
103 /// </summary>
104 /// <param name="dt1">左表（主表）</param>
105 /// <param name="dt2">右表</param>
106 /// <param name="FJC">左表中关联的字段名（字符串）</param>
107 /// <param name="SJC">右表中关联的字段名（字符串）</param>
108 /// <returns></returns>
109 public static DataTable Join(DataTable dt1, DataTable dt2, DataColumn[] FJC, DataColumn[] SJC)
110 {
111 //创建一个新的DataTable
112 DataTable table = new DataTable("Join");
113
114 // Use a DataSet to leverage DataRelation
115 using (DataSet ds = new DataSet())
116 {
117 //把DataTable Copy到DataSet中
118 ds.Tables.AddRange(new DataTable[] { dt1.Copy(), dt2.Copy() });
119
120 DataColumn[] First_columns = new DataColumn[FJC.Length];
121 for (int i = 0; i < First_columns.Length; i++)
122 {
123 First_columns[i] = ds.Tables[0].Columns[FJC[i].ColumnName];
124 }
125
126 DataColumn[] Second_columns = new DataColumn[SJC.Length];
127 for (int i = 0; i < Second_columns.Length; i++)
128 {
129 Second_columns[i] = ds.Tables[1].Columns[SJC[i].ColumnName];
130 }
131
132 //创建关联
133 DataRelation r = new DataRelation(string.Empty, First_columns, Second_columns, false);
134 ds.Relations.Add(r);
135
136 //为关联表创建列
137 for (int i = 0; i < dt1.Columns.Count; i++)
138 {
139 table.Columns.Add(dt1.Columns[i].ColumnName, dt1.Columns[i].DataType);
140 }
141
142 for (int i = 0; i < dt2.Columns.Count; i++)
143 {
144 //看看有没有重复的列，如果有在第二个DataTable的Column的列明后加_Second
145 if (!table.Columns.Contains(dt2.Columns[i].ColumnName))
146 table.Columns.Add(dt2.Columns[i].ColumnName, dt2.Columns[i].DataType);
147 else
148 table.Columns.Add(dt2.Columns[i].ColumnName + "_Second", dt2.Columns[i].DataType);
149 }
150
151 table.BeginLoadData();
152 int itable2Colomns = ds.Tables[1].Rows[0].ItemArray.Length;
153 foreach (DataRow firstrow in ds.Tables[0].Rows)
154 {
155 //得到行的数据
156 DataRow[] childrows = firstrow.GetChildRows(r);//第二个表关联的行
157 if (childrows != null && childrows.Length > 0)
158 {
159 object[] parentarray = firstrow.ItemArray;
160 foreach (DataRow secondrow in childrows)
161 {
162 object[] secondarray = secondrow.ItemArray;
163 object[] joinarray = new object[parentarray.Length + secondarray.Length];
164 Array.Copy(parentarray, 0, joinarray, 0, parentarray.Length);
165 Array.Copy(secondarray, 0, joinarray, parentarray.Length, secondarray.Length);
166 table.LoadDataRow(joinarray, true);
167 }
168
169 }
170 else//如果有外连接(Left Join)添加这部分代码
171 {
172 object[] table1array = firstrow.ItemArray;//Table1
173 object[] table2array = new object[itable2Colomns];
174 object[] joinarray = new object[table1array.Length + itable2Colomns];
175 Array.Copy(table1array, 0, joinarray, 0, table1array.Length);
176 Array.Copy(table2array, 0, joinarray, table1array.Length, itable2Colomns);
177 table.LoadDataRow(joinarray, true);
178 DataColumn[] dc = new DataColumn[2];
179 dc[0] = new DataColumn("");
180 }
181 }
182 table.EndLoadData();
183 }
184 return table;//***在此处打断点，程序运行后点击查看即可观察到结果
185 }
186
187 /// <summary>
188 /// 重载1
189 /// </summary>
190 /// <param name="dt1"></param>
191 /// <param name="dt2"></param>
192 /// <param name="FJC"></param>
193 /// <param name="SJC"></param>
194 /// <returns></returns>
195 public static DataTable Join(DataTable dt1, DataTable dt2, DataColumn FJC, DataColumn SJC)
196 {
197 return Join(dt1, dt2, new DataColumn[] { FJC }, new DataColumn[] { SJC });
198 }
199
200 /// <summary>
201 /// 重载2
202 /// </summary>
203 /// <param name="dt1"></param>
204 /// <param name="dt2"></param>
205 /// <param name="FJC"></param>
206 /// <param name="SJC"></param>
207 /// <returns></returns>
208 public static DataTable Join(DataTable dt1, DataTable dt2, string FJC, string SJC)
209 {
210 return Join(dt1, dt2, new DataColumn[] { dt1.Columns[FJC] }, new DataColumn[] { dt1.Columns[SJC] });
211 }
212
213 }
214 }
上面运行的结果：
这是通过网上整理的，适合处理两个服务器上的数据关联。欢迎留言。
时间： 2024-12-21 02:17:43