List<T> DataSet 转换
1.List-->DataSet
2.List<T>-->DataSet
3.DataSet-->List<T>
using System; using System.Collections; using System.Collections.Generic; using System.Linq; using System.Data; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using System.Text; using System.Reflection; public partial class Default2 : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { } /// <summary> /// 集合装换DataSet /// </summary> /// <param name="list">集合</param> /// <returns></returns> /// 2008-08-01 22:08 HPDV2806 public static DataSet ToDataSet(IList p_List) { DataSet result = new DataSet(); DataTable _DataTable = new DataTable(); if (p_List.Count > 0) { PropertyInfo[] propertys = p_List[0].GetType().GetProperties(); foreach (PropertyInfo pi in propertys) { _DataTable.Columns.Add(pi.Name, pi.PropertyType);//columnName Type } for (int i = 0; i < p_List.Count; i++) { ArrayList tempList = new ArrayList(); //一行数据的数组 foreach (PropertyInfo pi in propertys) { object obj = pi.GetValue(p_List[i], null);//p_List[i]是集合中的某一个对象，GetValue 返回其属性值 tempList.Add(obj); } object[] array = tempList.ToArray(); _DataTable.LoadDataRow(array, true); //LoadDataRow 查找和更新特定行。 如果找不到任何匹配行，则使用给定值创建新行 } } result.Tables.Add(_DataTable); return result; } /// <summary> /// 泛型集合转换DataSet /// </summary> /// <typeparam name="T"></typeparam> /// <param name="list">泛型集合</param> /// <returns></returns> /// 2008-08-01 22:43 HPDV2806 public static DataSet ToDataSet<T>(IList<T> list) { return ToDataSet<T>(list, null); } /// <summary> /// 泛型集合转换DataSet /// </summary> /// <typeparam name="T"></typeparam> /// <param name="p_List">泛型集合</param> /// <param name="p_PropertyName">待转换属性名数组(null时，表中字段全部转换，有数组时，只转换数组中和表字段都有的字段)</param> /// <returns></returns> /// 2008-08-01 22:44 HPDV2806 public static DataSet ToDataSet<T>(IList<T> p_List, params string[] p_PropertyName) { List<string> propertyNameList = new List<string>(); if (p_PropertyName != null) propertyNameList.AddRange(p_PropertyName); //AddRange 向……末尾，添加数组 DataSet result = new DataSet(); DataTable _DataTable = new DataTable(); if (p_List.Count > 0) { PropertyInfo[] propertys = p_List[0].GetType().GetProperties(); foreach (PropertyInfo pi in propertys) { if (propertyNameList.Count == 0) { // 没有指定属性的情况下全部属性都要转换 _DataTable.Columns.Add(pi.Name, pi.PropertyType); } else { if (propertyNameList.Contains(pi.Name)) _DataTable.Columns.Add(pi.Name, pi.PropertyType); } } for (int i = 0; i < p_List.Count; i++) { ArrayList tempList = new ArrayList(); foreach (PropertyInfo pi in propertys) { if (propertyNameList.Count == 0) { object obj = pi.GetValue(p_List[i], null); tempList.Add(obj); } else { if (propertyNameList.Contains(pi.Name)) { object obj = pi.GetValue(p_List[i], null); tempList.Add(obj); } } } object[] array = tempList.ToArray(); _DataTable.LoadDataRow(array, true); } } result.Tables.Add(_DataTable); return result; } /// <summary> /// DataSet装换为泛型集合 /// </summary> /// <typeparam name="T"></typeparam> /// <param name="p_DataSet">DataSet</param> /// <param name="p_TableIndex">待转换数据表索引</param> /// <returns></returns> /// 2008-08-01 22:46 HPDV2806 public static IList<T> DataSetToIList<T>(DataSet p_DataSet, int p_TableIndex) { if (p_DataSet == null || p_DataSet.Tables.Count < 0) return null; if (p_TableIndex > p_DataSet.Tables.Count - 1) return null; if (p_TableIndex < 0) p_TableIndex = 0; DataTable p_Data = p_DataSet.Tables[p_TableIndex]; // 返回值初始化 IList<T> result = new List<T>(); for (int i = 0; i < p_Data.Rows.Count; i++) { T _t = (T)Activator.CreateInstance(typeof(T));//Activator.CreateInstrance C#在类工厂中动态创建类的实例 PropertyInfo[] propertys = _t.GetType().GetProperties(); foreach (PropertyInfo pi in propertys) { for (int j = 0; j < p_Data.Columns.Count; j++) { // 属性与字段名称一致的进行赋值 if (pi.Name.Equals(p_Data.Columns[j].ColumnName)) { // 数据库NULL值单独处理 if (p_Data.Rows[i][j] != DBNull.Value) pi.SetValue(_t, p_Data.Rows[i][j], null); //SetValue 将给定对象的属性值设置为给定值。 else pi.SetValue(_t, null, null); break; } } } result.Add(_t); } return result; } /// <summary> /// DataSet装换为泛型集合 /// </summary> /// <typeparam name="T"></typeparam> /// <param name="p_DataSet">DataSet</param> /// <param name="p_TableName">待转换数据表名称</param> /// <returns></returns> /// 2008-08-01 22:47 HPDV2806 public static IList<T> DataSetToIList<T>(DataSet p_DataSet, string p_TableName) { int _TableIndex = 0; if (p_DataSet == null || p_DataSet.Tables.Count < 0) return null; if (string.IsNullOrEmpty(p_TableName)) return null; for (int i = 0; i < p_DataSet.Tables.Count; i++) { // 获取Table名称在Tables集合中的索引值 if (p_DataSet.Tables[i].TableName.Equals(p_TableName)) { _TableIndex = i; break; } } return DataSetToIList<T>(p_DataSet, _TableIndex); } }
+代码：
/// <summary> /// DataTable 转换成Ilist<T> /// </summary> /// <typeparam name="T"></typeparam> /// <param name="dt"></param> /// <returns></returns> public static IList<T> ConverToList(DataTable dt) { // 定义集合 IList<T> ts = new List<T>(); // 获得此模型的类型 Type type = typeof(T); foreach (DataRow dr in dt.Rows) { T t = new T(); // 获得此模型的公共属性 PropertyInfo[] propertys = t.GetType().GetProperties(); foreach (PropertyInfo pi in propertys) { string tempName = pi.Name; // 检查DataTable是否包含此列 if (dt.Columns.Contains(tempName)) { // 判断此属性是否有Setter if (!pi.CanWrite) continue; object value = null; if (pi.PropertyType.FullName == "System.String") { value = dr[tempName].ToString(); } else { value = dr[tempName]; } if (value != DBNull.Value) { pi.SetValue(t, value, null); } } } ts.Add(t); } return ts; } /// <summary> /// Datatable 转换为Model /// 需要保证datatable里只有一条数据，如果是多条数据，会抛出异常 /// </summary> /// <typeparam name="T"></typeparam> /// <param name="dt"></param> /// <returns></returns> public static T ConverToModel(DataTable dt) { if (dt.Rows.Count != 1) { throw new Exception("传入的datatable中有" + dt.Rows.Count + "数据,而该参数只能有一条数据"); } T t = new T(); PropertyInfo[] propertys = t.GetType().GetProperties(); foreach (PropertyInfo pi in propertys) { string tempName = pi.Name; // 检查DataTable是否包含此列 if (dt.Columns.Contains(tempName)) { // 判断此属性是否有Setter if (!pi.CanWrite) continue; object value = null; if (pi.PropertyType.FullName == "System.String") { value = dt.Rows[0][tempName].ToString(); } else { value = dt.Rows[0][tempName]; } if (value != DBNull.Value) { pi.SetValue(t, value, null); } } } return t; }
问题
Nullable转换
pi.SetValue(t, Convert.ChangeType(value, pi.PropertyType, CultureInfo.CurrentCulture), null);
