【2017001】IList转DataTable、DataTable转IList

IList转DataTable、DataTable转IList

 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Data;
 using System.Linq;
 using System.Reflection;
 using System.Text;

 namespace Framework.Utility
 {
     public static class DataTableHelper
     {
         public static DataTable ConvertTo<T>(IList<T> list)
         {
             DataTable table = CreateTable<T>();
             Type entityType = typeof(T);
             PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(entityType);
             foreach (T item in list)
             {
                 DataRow row = table.NewRow();
                 foreach (PropertyDescriptor prop in properties)
                     row[prop.Name] = prop.GetValue(item);
                 table.Rows.Add(row);
             }
             return table;
         }

         public static IList<T> ConvertTo<T>(IList<DataRow> rows)
         {
             IList<T> list = null;
             if (rows != null)
             {
                 list = new List<T>();
                 foreach (DataRow row in rows)
                 {
                     T item = CreateItem<T>(row);
                     list.Add(item);
                 }
             }
             return list;
         }

         public static IList<T> ConvertTo<T>(DataTable table)
         {
             try
             {
                 if (table == null)
                     return null;

                 List<DataRow> rows = new List<DataRow>();
                 foreach (DataRow row in table.Rows)
                     rows.Add(row);

                 return ConvertTo<T>(rows);
             }
             catch(Exception ex)
             {
                 string err = ex.ToString();
                 return null;
             }
         }

         public static T CreateItem<T>(DataRow row)
         {
             string columnName;
             T obj = default(T);
             if (row != null)
             {
                 obj = Activator.CreateInstance<T>();
                 foreach (DataColumn column in row.Table.Columns)
                 {
                     columnName = column.ColumnName;
                     //Get property with same columnName
                     PropertyInfo prop = obj.GetType().GetProperty(columnName);
                     if (prop == null) continue;
                     ) continue;
                     try
                     {
                         //Get value for the column
                         object value = (row[columnName].GetType() == typeof(DBNull))
                         ? null : row[columnName];
                         //Set property value
                         if (prop.CanWrite)    //判断其是否可写
                             prop.SetValue(obj, value, null);
                     }
                     catch
                     {
                         throw;

                     }
                 }
             }
             return obj;
         }

         public static DataTable CreateTable<T>()
         {
             Type entityType = typeof(T);
             DataTable table = new DataTable(entityType.Name);
             PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(entityType);

             foreach (PropertyDescriptor prop in properties)
                 table.Columns.Add(prop.Name, prop.PropertyType);

             return table;
         }
         /// <summary>
         /// datatable 转换成list
         /// 调用方法：List<Entity> list = DataTableHelper.ConvertToEx<Entity>(dt);
         /// </summary>
         /// <typeparam name="T"></typeparam>
         /// <param name="dt"></param>
         /// <returns></returns>
         public static List<T> ConvertToEx<T>(DataTable dt) where T : new()
         {
             if (dt == null) return null;
             ) return null;

             List<T> list = new List<T>();
             Type type = typeof(T);
             PropertyInfo[] propertyInfos = type.GetProperties();  //获取泛型的属性
             List<DataColumn> listColumns = dt.Columns.Cast<DataColumn>().ToList();  //获取数据集的表头，以便于匹配
             T t;
             foreach (DataRow dr in dt.Rows)
             {
                 t = new T();
                 foreach (PropertyInfo propertyInfo in propertyInfos)
                 {
                     try
                     {
                         DataColumn dColumn = listColumns.Find(name => name.ToString().ToUpper() == propertyInfo.Name.ToUpper());  //查看是否存在对应的列名
                         if (dColumn != null)
                             propertyInfo.SetValue(t, dr[propertyInfo.Name], null);  //赋值
                     }
                     catch (Exception ex)
                     {
                         throw new Exception(ex.Message);
                     }
                 }
                 list.Add(t);
             }
             return list;
         }

     }
 }