一、List<T>/IEnumerable转换到DataTable/DataView
private DataTable ToDataTable(List items){ var tb = new DataTable(typeof (T).Name); PropertyInfo[] props = typeof (T).GetProperties(BindingFlags.Public | BindingFlags.Instance); foreach (PropertyInfo prop in props) { Type t = GetCoreType(prop.PropertyType); tb.Columns.Add(prop.Name, t); } foreach (T item in items) { var values = new object[props.Length]; for (int i = 0; i < props.Length; i++) { values[i] = props[i].GetValue(item, null); } tb.Rows.Add(values); } return tb;} /// /// Determine of specified type is nullable/// public static bool IsNullable(Type t){ return !t.IsValueType || (t.IsGenericType && t.GetGenericTypeDefinition() == typeof(Nullable<>));} ////// Return underlying type if type is Nullable otherwise return the type/// public static Type GetCoreType(Type t){ if (t != null && IsNullable(t)) { if (!t.IsValueType) { return t; } else { return Nullable.GetUnderlyingType(t); } } else { return t; }}
方法二：
public static DataTable ToDataTable(IEnumerable collection) { var props = typeof(T).GetProperties(); var dt = new DataTable(); dt.Columns.AddRange(props.Select(p => new DataColumn(p.Name, p.PropertyType)).ToArray()); if (collection.Count() > 0) { for (int i = 0; i < collection.Count(); i++) { ArrayList tempList = new ArrayList(); foreach (PropertyInfo pi in props) { object obj = pi.GetValue(collection.ElementAt(i), null); tempList.Add(obj); } object[] array = tempList.ToArray(); dt.LoadDataRow(array, true); } } return dt; }
二、DataTable转换到List
方法一:
public static IListConvertTo (DataTable table) { if (table == null) { return null; } List rows = new List (); foreach (DataRow row in table.Rows) { rows.Add(row); } return ConvertTo (rows); } public static IList ConvertTo (IList rows) { IList list = null; if (rows != null) { list = new List (); foreach (DataRow row in rows) { T item = CreateItem (row); list.Add(item); } } return list;} public static T CreateItem (DataRow row) { T obj = default(T); if (row != null) { obj = Activator.CreateInstance (); foreach (DataColumn column in row.Table.Columns) { PropertyInfo prop = obj.GetType().GetProperty(column.ColumnName); try { object value = row[column.ColumnName]; prop.SetValue(obj, value, null); } catch { //You can log something here //throw; } } } return obj; }
把查询结果以DataTable返回很方便，但是在检索数据时又很麻烦，没有模型类型检索方便。
所以很多人都是按照以下方式做的：
// 获得查询结果 DataTable dt = DbHelper.ExecuteDataTable(...); // 把DataTable转换为IList<UserInfo> IList<UserInfo> users = ConvertToUserInfo(dt); 问题：如果此系统有几十上百个模型，那不是每个模型中都要写个把DataTable转换为此模型的方法吗？
解决：能不能写个通用类，可以把DataTable转换为任何模型，呵呵，这就需要利用反射和泛型了
using System; using System.Collections.Generic; using System.Text; using System.Data; using System.Reflection; namespace NCL.Data { /// /// 实体转换辅助类 /// public class ModelConvertHelper where T : new() { public static IList ConvertToModel(DataTable dt) { // 定义集合 IList ts = new List (); // 获得此模型的类型 Type type = typeof(T); string tempName = ""; 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) { 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 = dr[tempName]; if (value != DBNull.Value) pi.SetValue(t, value, null); } } ts.Add(t); } return ts; } } }
使用方式：
DataTable dt = DbHelper.ExecuteDataTable(...); // 把DataTable转换为IList<UserInfo> IList<UserInfo> users = ModelConvertHelper<UserInfo>.ConvertToModel(dt); 本文转自：http://www.okbase.net/doc/details/3282