DataTable使用总结

1.DataTable数据去重

 1  static void Main(string[] args)
 2         {
 3             DataTable dt = new DataTable();//创建表
 4             DataColumn dc = null;//创建列
 5             int fieldCount = 4;//列数
 6             int rowCount = 4;//行数
 7             //以下两个循环只是模拟向dt中添加数据
 8             for (int i = 0; i < fieldCount; i++)
 9             {
10                 if (i==0)
11                 {
12                     dc = dt.Columns.Add("ID", Type.GetType("System.String"));
13                 }
14                 else
15                 {
16                     dc = dt.Columns.Add(string.Format("第{0}列", i.ToString()), Type.GetType("System.String"));
17                 }
18             }
19             for (int i = 0; i < rowCount; i++)
20             {
21                 DataRow newRow = dt.NewRow();
22                 for (int j = 0; j < fieldCount; j++)
23                 {
24                     if (j==0)
25                     {
26                         newRow["ID"] = Guid.NewGuid();
27                     }
28                     else
29                     {
30                         newRow[string.Format("第{0}列", j.ToString())] = j;
31                     }
32                 }
33                 dt.Rows.Add(newRow);
34             }
35             //数据去重处理
36             DataTable finalltable = dt.Clone();
37             finalltable.Clear();
38             var rows = from row in dt.AsEnumerable()
39                        group row
40                        by row["第1列"]//表示根据具体的哪一列进行去重
41                        into myrow
42                        select myrow.FirstOrDefault();
43             foreach (DataRow row in rows)
44             {
45                 finalltable.ImportRow(row);
46             }
47         }

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