转换list数据为table 和 转换table为list的两个方法

　　　　　/// <summary>
        /// Convert  list to Data Table
        /// </summary>
        /// <typeparam name="T">Target Class</typeparam>
        /// <param name="varlist">list you want to convert it to Data Table</param>
        /// <returns>Data Table That Represent List data</returns>
        public static DataTable ToADOTable<T>(this IEnumerable<T> varlist)
        {
            DataTable toReturn = new DataTable();

            // Could add a check to verify that there is an element 0
            T TopRec = varlist.ElementAtOrDefault(0);

            if (TopRec == null)
                return toReturn;

            // Use reflection to get property names, to create table
            // column names

            PropertyInfo[] oProps = ((Type)TopRec.GetType()).GetProperties();

            foreach (PropertyInfo pi in oProps)
            {
                Type pt = pi.PropertyType;
                if (pt.IsGenericType && pt.GetGenericTypeDefinition() == typeof(Nullable<>))
                    pt = Nullable.GetUnderlyingType(pt);
                toReturn.Columns.Add(pi.Name, pt);
            }

            foreach (T rec in varlist)
            {
                DataRow dr = toReturn.NewRow();
                foreach (PropertyInfo pi in oProps)
                {
                    object o = pi.GetValue(rec, null);

                    if (o == null)
                        dr[pi.Name] = DBNull.Value;
                    else
                        dr[pi.Name] = o;
                }
                toReturn.Rows.Add(dr);
            }

            return toReturn;
        }

         /// <summary>
        /// Convert Data Table To List of Type T
        /// </summary>
        /// <typeparam name="T">Target Class to convert data table to List of T </typeparam>
        /// <param name="datatable">Data Table you want to convert it</param>
        /// <returns>List of Target Class</returns>
        public  static List<T> ToList<T>(this DataTable datatable) where T : new()
        {
            List<T> Temp = new List<T>();
            try
            {
                List<string> columnsNames = new List<string>();
                foreach (DataColumn DataColumn in datatable.Columns)
                    columnsNames.Add(DataColumn.ColumnName);
                Temp = datatable.AsEnumerable().ToList().ConvertAll<T>(row => getObject<T>(row, columnsNames));
                return Temp;
            }
            catch { return Temp; }
        }

        public static T getObject<T>(DataRow row, List<string> columnsName) where T : new()
        {
            T obj = new T();
            try
            {
                string columnname = "";
                string value = "";
                PropertyInfo[] Properties; Properties = typeof(T).GetProperties();
                foreach (PropertyInfo objProperty in Properties)
                {
                    columnname = columnsName.Find(name => name.ToLower() == objProperty.Name.ToLower());
                    if (!string.IsNullOrEmpty(columnname))
                    {
                        value = row[columnname].ToString();
                        if (!string.IsNullOrEmpty(value))
                        {
                            if (Nullable.GetUnderlyingType(objProperty.PropertyType) != null)
                            {
                                value = row[columnname].ToString().Replace("$", "").Replace(",", "");
                                objProperty.SetValue(obj, Convert.ChangeType(value, Type.GetType(Nullable.GetUnderlyingType(objProperty.PropertyType).ToString())), null);
                            }
                            else
                            {
                                value = row[columnname].ToString().Replace("%", "");
                                if (!(value == "System.Byte[]"))
                                    objProperty.SetValue(obj, Convert.ChangeType(value, Type.GetType(objProperty.PropertyType.ToString())), null);
                                else
                                    objProperty.SetValue(obj, row[columnname], null);
                            }
                        }
                    }
                } return obj;
            }
            catch { return obj; }
        }
    

标签：转换,List,list,value,columnname,objProperty,table,pi,row
来源： https://www.cnblogs.com/kelenote/p/15978953.html