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DataTable扩展方法ToList<T>()、ToJSON()、ToArrayList()
/// <summary> /// 扩展方法类 /// </summary> public static class CommonExtension { /// <summary> /// 数据类型对应转换方法字典 /// </summary> static Dictionary<Type, Func<object, object>> dic_convert = new Dictionary<Type, Func<object, object>>(); /// <summary> /// 构造函数 /// </summary> static CommonExtension() { Func<object, object> f = null; //string f = (val) => Convert.ToString(val); dic_convert.Add(typeof(string), f); //int f = (val) => Convert.ToInt32(val); dic_convert.Add(typeof(int), f); //long f = (val) => Convert.ToInt64(val); dic_convert.Add(typeof(long), f); //double f = (val) => Convert.ToDouble(val); dic_convert.Add(typeof(double), f); //float f = (val) => (float)(val); dic_convert.Add(typeof(float), f); //decimal f = (val) => Convert.ToDecimal(val); dic_convert.Add(typeof(decimal), f); //datetime f = (val) => Convert.ToDateTime(val); dic_convert.Add(typeof(DateTime), f); //bool f = (val) => Convert.ToBoolean(val); dic_convert.Add(typeof(bool), f); //byte f = (val) => Convert.ToByte(val); dic_convert.Add(typeof(byte), f); //char f = (val) => Convert.ToChar(val); dic_convert.Add(typeof(char), f); //null f = (val) => (null); dic_convert.Add(typeof(DBNull), f); } /// <summary> /// 获取DataTable的列名集合 /// </summary> public static IList<string> GetColumnNames(this DataTable dt) { if (dt == null || dt.Rows.Count == 0) { return new List<string>(0); } //由于集合中的元素是确定的，所以可以指定元素的个数，系统就不会分配多余的空间，效率会高点 IList<string> list = new List<string>(dt.Columns.Count); foreach (DataColumn dc in dt.Columns) { list.Add(dc.ColumnName); } return list; } /// <summary> /// 将 DataTable 序列化成 json 字符串 /// </summary> /// <param name="dt"></param> /// <returns></returns> public static string ToJson(this DataTable dt) { if (dt == null || dt.Rows.Count == 0) { return "[]"; } JavaScriptSerializer myJson = new JavaScriptSerializer(); List<Dictionary<string, object>> list = new List<Dictionary<string, object>>(); foreach (DataRow dr in dt.Rows) { Dictionary<string, object> result = new Dictionary<string, object>(); foreach (DataColumn dc in dt.Columns) { result.Add(dc.ColumnName, dr[dc].ToString()); } list.Add(result); } return myJson.Serialize(list); } /// <summary> /// 将 DataTable 序列化成 ArrayList /// </summary> /// <param name="dt"></param> /// <returns></returns> public static ArrayList ToArrayList(this DataTable dt) { ArrayList arrayList = new ArrayList(); if (dt != null) { foreach (DataRow dataRow in dt.Rows) { Dictionary<string, object> dictionary = new Dictionary<string, object>(); //实例化一个参数集合 foreach (DataColumn dataColumn in dt.Columns) { dictionary.Add(dataColumn.ColumnName, dataRow[dataColumn.ColumnName].ToString()); } arrayList.Add(dictionary); } } return arrayList; } /// <summary> /// 把DataTable转换成泛型列表 /// </summary> /// <typeparam name="T">类型</typeparam> /// <param name="dt"></param> /// <returns></returns> public static List<T> ToList<T>(this DataTable dt) where T : new() { var list = new List<T>(); if (dt == null || dt.Rows.Count == 0) { return list; } // 获得此模型的公共属性 var plist = new List<PropertyInfo>(typeof(T).GetProperties()); // 循环行 foreach (DataRow row in dt.Rows) { var t = new T(); // 循环列 foreach (DataColumn dc in dt.Columns) { var value =http://www.mamicode.com/ row[dc.ColumnName]; // 判断值是否有效 if (Convert.IsDBNull(value)) continue; //var p = info.GetType().GetProperty(dc.ColumnName); var p = plist.FirstOrDefault(c => c.Name.Equals(dc.ColumnName, StringComparison.CurrentCultureIgnoreCase)); // 判断此属性是否有Setter if (p == null || !p.CanWrite) continue; if (dic_convert.ContainsKey(p.PropertyType)) { var val = dic_convert[p.PropertyType].Invoke(value); p.SetValue(t, val, null); } } list.Add(t); } dt.Dispose(); dt = null; return list; } /// <summary> /// 将DataTable实例转换成List<T> /// </summary> /// <typeparam name="T">Model类型</typeparam>列表 /// <param name="dt">DataTable对象</param> /// <returns></returns> public static List<T> ToListSmart<T>(this DataTable dt) where T : new() { // 定义集合 List<T> list = new List<T>(); if (dt == null || dt.Rows.Count == 0) { return list; } // 获得此模型的类型 Type type = typeof(T); // 获得此模型的公共属性 var plist = new List<PropertyInfo>(type.GetProperties()); // 获取列的个数 int col_cnt = dt.Columns.Count; T t; if (plist.Count >= col_cnt) { #region 循环列给属性赋值方式 foreach (DataRow row in dt.Rows) { t = new T(); // 循环列 foreach (DataColumn dc in dt.Columns) { // 根据列名查找属性 PropertyInfo pi = plist.Find(p => p.Name.Equals(dc.ColumnName, StringComparison.CurrentCultureIgnoreCase)); if (pi != null) { // 判断此属性是否有Setter if (!pi.CanWrite) continue; // 判断值是否有效 if (Convert.IsDBNull(row[pi.Name])) continue; if (dic_convert.ContainsKey(pi.PropertyType)) { var val = dic_convert[pi.PropertyType].Invoke(row[pi.Name]); pi.SetValue(t, val, null); } } } list.Add(t); } #endregion } else { #region 循环属性查找列对应的值 foreach (DataRow row in dt.Rows) { t = System.Activator.CreateInstance<T>(); // 循环属性列表 foreach (PropertyInfo pi in plist) { // 检查DataTable是否包含此列 if (dt.Columns.Contains(pi.Name)) { // 判断此属性是否有Setter if (!pi.CanWrite) continue; // 判断值是否有效 if (row[pi.Name] == DBNull.Value) continue; if (dic_convert.ContainsKey(pi.PropertyType)) { var val = dic_convert[pi.PropertyType].Invoke(row[pi.Name]); pi.SetValue(t, val, null); } } } list.Add(t); } #endregion } return list; } #endregion }
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