將DataTable轉為自訂物件List<class>

自定義的class

1. public class UserInfo
2. {
3. public int ID{get;set;}
4. public string Name{get;set;}
5. public double weight{get;set;}
6. public DataTime UpdateDate{get;set;}
7. }

而這是取得DataTable資料的function，為求Demo而塞一些假資料

1. static private DataTable GetDataTable()
2. {
3. DataTable dt - new DataTable();
4. dt.Columns.Add("ID");
5. dt.Columns.Add("Name");
6. dt.Columns.Add("weight");
7. dt.Columns.Add("UpdateDate");
9. for(int i=0;i<10;i++)
10. {
11. DataRow dr = dt.NewRow();
12. dr["ID"] =i;
13. dr["Name"]="User"+i;
14. dr["weight"]=23;
15. dr["UpdateDate"]=DateTime.Now;
16. dt.Rows.Add(dr);
17. }
18. return dt;
19. }

而實際轉換的function如下，而通常我會新增一個class，讓其他程式能共用

1. public static class DataTableExtensions
2. {
3. public static IList<T> ToList<T>(this DataTable table) where T : new()
4. {
5. IList<PropertyInfo> properties = typeof(T).GetProperties().ToList();
6. IList<T> result = new List<T>();
8. //取得DataTable所有的row data
9. foreach (var row in table.Rows)
10. {
11. var item = MappingItem<T>((DataRow)row, properties);
12. result.Add(item);
13. }
15. return result;
16. }
18. private static T MappingItem<T>(DataRow row, IList<PropertyInfo> properties) where T : new()
19. {
20. T item = new T();
21. foreach (var property in properties)
22. {
23. if (row.Table.Columns.Contains(property.Name))
24. {
25. //針對欄位的型態去轉換
26. if (property.PropertyType == typeof(DateTime))
27. {
28. DateTime dt = new DateTime();
29. if (DateTime.TryParse(row[property.Name].ToString(), out dt))
30. {
31. property.SetValue(item, dt, null);
32. }
33. else
34. {
35. property.SetValue(item, null, null);
36. }
37. }
38. else if (property.PropertyType == typeof(decimal))
39. {
40. decimal val = new decimal();
41. decimal.TryParse(row[property.Name].ToString(), out val);
42. property.SetValue(item, val, null);
43. }
44. else if(property.PropertyType == typeof(double))
45. {
46. double val = new double();
47. double.TryParse(row[property.Name].ToString(), out val);
48. property.SetValue(item, val, null);
49. }
50. else if (property.PropertyType == typeof(int))
51. {
52. int val = new int();
53. int.TryParse(row[property.Name].ToString(), out val);
54. property.SetValue(item, val, null);
55. }
56. else
57. {
58. if (row[property.Name] != DBNull.Value)
59. {
60. property.SetValue(item, row[property.Name], null);
61. }
62. }
63. }
64. }
65. return item;
66. }
67. }

使用方式:

1. List<UserInfo> list = new List<UserInfo>();
2. DataTable dt = GetDataTable();
3. var result = DataTableExtensions.ToList<UserInfo>(dt).ToList();
4. list = result.OrderBy(c => c.UpdateDate).ToList();