c# DataTable 数据集处理DataTableHandler

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Collections;
using System.IO;
using System.Xml.Serialization;

namespace HuaTong.General.Utility
{
    /// <summary>
    /// 数据集处理
    /// </summary>
    public static class DataTableHandler
    {
        /// <summary>  
        /// 检查DataSet是否可用
        /// </summary>  
        public static bool CheckData(this DataSet ds, int valNum)
        {
            var flag = ds != null && ds.Tables.Count > 0;
            if (flag)
            {
                int count = 0;
                for (var i = 0; i < valNum; i++)
                {
                    var dtflag = ds.Tables[i].CheckData();
                    if (dtflag) count++;
                }
                return count == valNum;
            }
            return flag;
        }

        /// <summary>
        /// 检查DataTable是否可用
        /// </summary>
        public static bool CheckData(this DataTable dt)
        {
            return dt != null && dt.Rows.Count > 0;
        }

        /// <summary>  
        /// 检查DataSet是否可用
        /// </summary>  
        public static DataRow FirstRow(this DataSet ds)
        {
            return ds.Tables[0].FirstRow();
        }

        /// <summary>
        /// 检查DataTable是否可用
        /// </summary>
        public static DataRow FirstRow(this DataTable dt)
        {
            return dt.Rows[0];
        }

        /// <summary>
        /// DataTable转换为List
        /// </summary>
        public static List<T> ToList<T>(this DataTable dt)
            where T : new()
        {

            List<T> list = new List<T>();

            foreach (DataRow dr in dt.Rows)
            {
                T t = dr.ToEntity<T>();
                //对象添加到泛型集合中
                list.Add(t);
            }
            return list;
        }

        /// <summary>
        /// DataRow转换为实体
        /// </summary>
        public static T ToEntity<T>(this DataRow dr)
            where T : new()
        {
            if (dr == null)
            {
                return default(T);
            }

            T model = new T();
            var props = ModelHandler.PropCache(model);
            for (int i = 0; i < dr.Table.Columns.Count; i++)
            {
                if (props.Any(m => StringHelper.IsEqualString(m.Name, dr.Table.Columns[i].ColumnName)))
                {
                    var prop = props.Single(m => StringHelper.IsEqualString(m.Name, dr.Table.Columns[i].ColumnName));
                    if (dr[i] != null && dr[i] != DBNull.Value)
                    {
                        prop.SetValue(model, Convert.ChangeType(dr[i], prop.PropertyType), null);
                    }
                }
            }
            return model;
        }

        /// <summary>
        /// List转换为DataTable
        /// </summary>
        public static DataTable ToDataTable<T>(this List<T> items)
        {
            var tb = new DataTable(typeof(T).Name);

            PropertyInfo[] props = ModelHandler.PropCache<T>();

            foreach (PropertyInfo prop in props)
            {
                Type t = ModelHandler.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;
        }

        /// <summary>
        /// DataTable转换为XML
        /// </summary>
        public static string ToXML(this DataTable dt)
        {
            if (!string.IsNullOrEmpty(dt.TableName))
            {
                dt.TableName = "datatable_1";
            }
            //xml序列化对象
            XmlSerializer xmlSerial = new XmlSerializer(typeof(DataTable));
            StringWriter sw = new StringWriter();
            xmlSerial.Serialize(sw, dt); // 序列化table
            StringReader sr = new StringReader(sw.ToString());
            return sr.ReadToEnd();
        }
    }
}