比较全面DataRow的映射的helper，兼测lambda方式的快速SetValue方法（测试结果大大出乎意料）

最近连续看到几篇关于把DataRow映射为实体类的Helper

http://www.cnblogs.com/inday/archive/2008/12/23/1360495.html 

http://www.cnblogs.com/yyliuliang/archive/2008/12/22/1358736.html 

但是这2个helper都有不全，就是对NullAble和Enum都支持的不好。

如：以下的测试代码，对于Nullable类型，都不能通过测试，枚举类型

[Test]
        public void T3()
        {
            var table = new DataTable("table");
            table.Columns.Add(new DataColumn("s", typeof(string)));
            table.Columns.Add(new DataColumn("i", typeof(string)));
            table.Columns.Add(new DataColumn("b", typeof(string)));

            DataRow row = table.NewRow();
            row["s"] = "s";
            row["i"] = "1";
            row["b"] = "true";

            var info = ModelHelper.ConvertModel<Model>(row);
            Assert.IsNotNull(info);
            Assert.AreEqual(info.B, true);
            Assert.AreEqual(info.i, 1);
            Assert.AreEqual(info.S, "s");
        }
public class Model
    {
        public string S { get; set; }
        public E1 E1 { get; set; }
        public int? i { get; set; }
        public bool B { get; set; }
    }

    public enum E1
    {
        a,
        b,
        c
    }

我现在的MVC项目中的Helper也有DataRowToModel的代码，对Nullable和Enum实现了兼容。

主要代码为如下的转换代码（ps：这边分代码是更具MVC中的相关代码简化改进而来，MVC中还支持复杂类型）

/// <summary>
        /// Converts the type of the simple.
        /// </summary>
        /// <param name="culture">The culture.</param>
        /// <param name="value">The value.</param>
        /// <param name="destinationType">Type of the destination.</param>
        /// <returns></returns>
        public static object ConvertSimpleType(CultureInfo culture, object value, Type destinationType)
        {
            if (value == null || destinationType.IsInstanceOfType(value))
            {
                return value;
            }
            if (value == DBNull.Value)
            {
                return null;
            }
            // if this is a user-input value but the user didn't type anything, return no value
            var valueAsString = value as string;
            if (valueAsString != null && valueAsString.Length == 0)
            {
                return null;
            }

            TypeConverter converter = TypeDescriptor.GetConverter(destinationType);
            if (destinationType.IsGenericType && destinationType.GetGenericTypeDefinition().Equals(typeof (Nullable<>))
                && value.GetType() != typeof (string))
            {
                var nulla = new NullableConverter(destinationType);
                destinationType = nulla.UnderlyingType;
                if (destinationType.IsEnum)
                {
                    return Enum.ToObject(destinationType, value);
                }
            }

            bool canConvertFrom = converter.CanConvertFrom(value.GetType());
            if (!canConvertFrom)
            {
                converter = TypeDescriptor.GetConverter(value.GetType());
            }

            if (!(canConvertFrom || converter.CanConvertTo(destinationType)))
            {
                if (destinationType.IsEnum)
                {
                    return Enum.ToObject(destinationType, value);
                }
            }

            try
            {
                object convertedValue = (canConvertFrom)
                                            ? converter.ConvertFrom(null, culture, value)
                                            : converter.ConvertTo(null, culture, value, destinationType);
                return convertedValue;
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
                string message = String.Format(CultureInfo.CurrentUICulture, value.GetType().FullName,
                                               destinationType.FullName);
                throw new InvalidOperationException(message, ex);
            }
        }

 下面是测试代码

using System;
using System.Data;
using System.Diagnostics;
using NUnit.Framework;

namespace Helper
{
    [TestFixture]
    public class Test
    {
        [Test]
        public void T1()
        {
            var table = new DataTable("table");
            table.Columns.Add(new DataColumn("s", typeof (string)));
            table.Columns.Add(new DataColumn("e1", typeof (string)));
            table.Columns.Add(new DataColumn("e2", typeof(string)));
            table.Columns.Add(new DataColumn("i1", typeof (string)));
            table.Columns.Add(new DataColumn("i2", typeof(string)));
            table.Columns.Add(new DataColumn("b1", typeof (string)));
            table.Columns.Add(new DataColumn("b2", typeof(string)));

            DataRow row = table.NewRow();
            row["s"] = "s";
            row["e1"] = "b";
            row["e2"] = "c";
            row["i1"] = "1";
            row["i2"] = "2";
            row["b1"] = "true";
            row["b2"] = "true";

            var info = ModelHelper.DataRowToModel<Model>(row);
            Assert.IsNotNull(info);
            Assert.AreEqual(info.B1, true);
            Assert.AreEqual(info.B2, true);
            Assert.AreEqual(info.E1, E1.b);
            Assert.AreEqual(info.E2, E1.c);
            Assert.AreEqual(info.i1, 1);
            Assert.AreEqual(info.i2, 2);
            Assert.AreEqual(info.S, "s");


            row = table.NewRow();
            row["s"] = "s";
            row["e1"] = "1";
            row["e2"] = "2";
            row["i1"] = "1";
            row["i2"] = "2";
            row["b1"] = "true";
            row["b2"] = "true";

            info = ModelHelper.DataRowToModel<Model>(row);
            Assert.IsNotNull(info);
            Assert.AreEqual(info.B1, true);
            Assert.AreEqual(info.B2, true);
            Assert.AreEqual(info.E1, E1.b);
            Assert.AreEqual(info.E2, E1.c);
            Assert.AreEqual(info.i1, 1);
            Assert.AreEqual(info.i2, 2);
            Assert.AreEqual(info.S, "s");
        }

        [Test]
        public void T2()
        {
            var table = new DataTable("table");
            table.Columns.Add(new DataColumn("s", typeof (string)));
            table.Columns.Add(new DataColumn("e1", typeof (int)));
            table.Columns.Add(new DataColumn("e2", typeof(int)));
            table.Columns.Add(new DataColumn("i1", typeof (int)));
            table.Columns.Add(new DataColumn("i2", typeof(int)));
            table.Columns.Add(new DataColumn("b1", typeof (bool)));
            table.Columns.Add(new DataColumn("b2", typeof(bool)));

            DataRow row = table.NewRow();
            row["s"] = "s";
            row["e1"] = 1;
            row["e2"] = 2;
            row["i1"] = 1;
            row["i2"] = 2;
            row["b1"] = "true";
            row["b2"] = "true";

            var info = ModelHelper.DataRowToModel<Model>(row);
            Assert.IsNotNull(info);
            Assert.AreEqual(info.B1, true);
            Assert.AreEqual(info.E1, E1.b);
            Assert.AreEqual(info.i1, 1);
            Assert.AreEqual(info.S, "s");
        }
        
        [Test]
        public void TestPerformance()
        {
            var table = new DataTable("table");
            table.Columns.Add(new DataColumn("s", typeof (string)));
            table.Columns.Add(new DataColumn("e1", typeof (int)));
            table.Columns.Add(new DataColumn("i1", typeof (int)));
            table.Columns.Add(new DataColumn("b", typeof (bool)));

            DataRow row = table.NewRow();
            row["s"] = "s";
            row["e1"] = 1;
            row["i1"] = 1;
            row["b"] = true;

            var timer = new Stopwatch();
            timer.Start();
            for (int i = 0; i < 1*10000; i++)
            {
                ModelHelper.DataRowToModel<Model>(row);
            }
            timer.Stop();
            Console.WriteLine(timer.ElapsedMilliseconds + "\t");

            var timer1 = new Stopwatch();
            timer1.Start();
            for (int i = 0; i < 1*10000; i++)
            {
                ModelHelper.FastDataRowToModel<Model>(row);
            }
            timer1.Stop();
            Console.WriteLine(timer1.ElapsedMilliseconds + "\t");
        }
    }

    public class Model
    {
        public string S { get; set; }
        public E1 E1 { get; set; }
        public E1? E2 { get; set; }
        public int i1 { get; set; }
        public int? i2 { get; set; }
        public bool B1 { get; set; }
        public bool? B2 { get; set; }
    }

    public enum E1
    {
        a,
        b,
        c
    }
}

 
前2天刚好看到”时不我待“的

自己动手写个ORM实现(4) 关于反射DataRow数据记录到实体性能的优化

写这篇文章的时候顺便做了一下测试，比较一下lambda语法和反射的语法到底是否如”时不我待“说的那样有数量级上的区别

但是测试的结果确大大出乎意料，是数量级上的区别不过是相反的，反射时间远远小于lambad语法的时间

测试1W次，反射时间：197 lambad时间：5574

下面是我的测试代码

[Test]
        public void TestPerformance()
        {
            var table = new DataTable("table");
            table.Columns.Add(new DataColumn("s", typeof (string)));
            table.Columns.Add(new DataColumn("e1", typeof (int)));
            table.Columns.Add(new DataColumn("i1", typeof (int)));
            table.Columns.Add(new DataColumn("b", typeof (bool)));

            DataRow row = table.NewRow();
            row["s"] = "s";
            row["e1"] = 1;
            row["i1"] = 1;
            row["b"] = true;

            var timer = new Stopwatch();
            timer.Start();
            for (int i = 0; i < 1*10000; i++)
            {
                ModelHelper.DataRowToModel<Model>(row);
            }
            timer.Stop();
            Console.WriteLine(timer.ElapsedMilliseconds + "\t");

            var timer1 = new Stopwatch();
            timer1.Start();
            for (int i = 0; i < 1*10000; i++)
            {
                ModelHelper.FastDataRowToModel<Model>(row);
            }
            timer1.Stop();
            Console.WriteLine(timer1.ElapsedMilliseconds + "\t");
        }
    }

下面是sln，包含class和测试

/Files/haptear/Helper.rar