1 public class DataHelper
2 {
3 #region IList如何转成List<T>
4 /// <summary>
5 /// IList如何转成List<T>
6 /// </summary>
7 /// <typeparam name="T"></typeparam>
8 /// <param name="list"></param>
9 /// <returns></returns>
10 public static List<T> IListToList<T>
(IList list)
11 {
12 T[] array =
new T[list.Count];
13 list.CopyTo(array,
0);
14 return new List<T>
(array);
15 }
16 #endregion
17
18 #region DataTable根据条件过滤表的内容
19 /// <summary>
20 /// 根据条件过滤表的内容
21 /// </summary>
22 /// <param name="dt"></param>
23 /// <param name="condition"></param>
24 /// <returns></returns>
25 public static DataTable DataFilter(DataTable dt,
string condition)
26 {
27 if (DataHelper.IsExistRows(dt))
28 {
29 if (condition.Trim() ==
"")
30 {
31 return dt;
32 }
33 else
34 {
35 DataTable newdt =
new DataTable();
36 newdt =
dt.Clone();
37 DataRow[] dr =
dt.Select(condition);
38 for (
int i =
0; i < dr.Length; i++
)
39 {
40 newdt.ImportRow((DataRow)dr[i]);
41 }
42 return newdt;
43 }
44 }
45 else
46 {
47 return null;
48 }
49 }
50 public static DataTable DataFilter(DataTable dt,
string condition,
string sort)
51 {
52 if (DataHelper.IsExistRows(dt))
53 {
54 DataTable newdt =
new DataTable();
55 newdt =
dt.Clone();
56 DataRow[] dr =
dt.Select(condition, sort);
57 for (
int i =
0; i < dr.Length; i++
)
58 {
59 newdt.ImportRow((DataRow)dr[i]);
60 }
61 return newdt;
62 }
63 else
64 {
65 return null;
66 }
67 }
68 #endregion
69
70 #region 检查DataTable 是否有数据行
71 /// <summary>
72 /// 检查DataTable 是否有数据行
73 /// </summary>
74 /// <param name="dt">DataTable</param>
75 /// <returns></returns>
76 public static bool IsExistRows(DataTable dt)
77 {
78 if (dt !=
null && dt.Rows.Count >
0)
79 return true;
80
81 return false;
82 }
83 #endregion
84
85 #region DataTable 转 DataTableToHashtable
86 /// <summary>
87 /// DataTable 转 DataTableToHashtable
88 /// </summary>
89 /// <param name="dt"></param>
90 /// <returns></returns>
91 public static Hashtable DataTableToHashtable(DataTable dt)
92 {
93 Hashtable ht =
new Hashtable();
94 foreach (DataRow dr
in dt.Rows)
95 {
96 for (
int i =
0; i < dt.Columns.Count; i++
)
97 {
98 string key =
dt.Columns[i].ColumnName;
99 ht[key] =
dr[key];
100 }
101 }
102 return ht;
103 }
104 #endregion
105
106 #region List转换DataTable
107 /// <summary>
108 /// 将泛类型集合List类转换成DataTable
109 /// </summary>
110 /// <param name="list">泛类型集合</param>
111 /// <returns></returns>
112 public static DataTable ListToDataTable<T>(List<T>
entitys)
113 {
114 //检查实体集合不能为空
115 if (entitys ==
null || entitys.Count <
1)
116 {
117 throw new Exception(
"需转换的集合为空");
118 }
119 //取出第一个实体的所有Propertie
120 Type entityType = entitys[
0].GetType();
121 PropertyInfo[] entityProperties =
entityType.GetProperties();
122
123 //生成DataTable的structure
124 //生产代码中，应将生成的DataTable结构Cache起来，此处略
125 DataTable dt =
new DataTable();
126 for (
int i =
0; i < entityProperties.Length; i++
)
127 {
128 //dt.Columns.Add(entityProperties[i].Name, entityProperties[i].PropertyType);
129 dt.Columns.Add(entityProperties[i].Name);
130 }
131 //将所有entity添加到DataTable中
132 foreach (
object entity
in entitys)
133 {
134 //检查所有的的实体都为同一类型
135 if (entity.GetType() !=
entityType)
136 {
137 throw new Exception(
"要转换的集合元素类型不一致");
138 }
139 object[] entityValues =
new object[entityProperties.Length];
140 for (
int i =
0; i < entityProperties.Length; i++
)
141 {
142 entityValues[i] = entityProperties[i].GetValue(entity,
null);
143 }
144 dt.Rows.Add(entityValues);
145 }
146 return dt;
147 }
148 #endregion
149
150 #region DataTable/DataSet 转 XML
151 /// <summary>
152 /// DataTable 转 XML
153 /// </summary>
154 /// <param name="dt"></param>
155 /// <returns></returns>
156 public static string DataTableToXML(DataTable dt)
157 {
158 if (dt !=
null)
159 {
160 if (dt.Rows.Count >
0)
161 {
162 System.IO.StringWriter writer =
new System.IO.StringWriter();
163 dt.WriteXml(writer);
164 return writer.ToString();
165 }
166 }
167 return String.Empty;
168 }
169 /// <summary>
170 /// DataSet 转 XML
171 /// </summary>
172 /// <param name="ds"></param>
173 /// <returns></returns>
174 public static string DataSetToXML(DataSet ds)
175 {
176 if (ds !=
null)
177 {
178 System.IO.StringWriter writer =
new System.IO.StringWriter();
179 ds.WriteXml(writer);
180 return writer.ToString();
181 }
182 return String.Empty;
183 }
184 #endregion
185
186 #region DataRow 转 HashTable
187 /// <summary>
188 /// DataRow 转 HashTable
189 /// </summary>
190 /// <param name="dr"></param>
191 /// <returns></returns>
192 public static Hashtable DataRowToHashTable(DataRow dr)
193 {
194 Hashtable htReturn =
new Hashtable(dr.ItemArray.Length);
195 foreach (DataColumn dc
in dr.Table.Columns)
196 htReturn.Add(dc.ColumnName, dr[dc.ColumnName]);
197 return htReturn;
198 }
199 #endregion
200 }
转载于:https://www.cnblogs.com/taigasweet/p/10676117.html
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