Andrew的部落格

1.Distinct

a.get datatable

IEnumerable<DataRow> query = (from c in contact.AsEnumerable()
                              select c).Take(100);

DataTable contactsTableWith100Rows = query.CopyToDataTable();

b.use Distinct operator

List<DataRow> rows = new List<DataRow>();

Average

取得平均價格

var query = from product in products
            group product by product.Field<string>("Style") into g
            select new
            {
                Style = g.Key,
                AverageListPrice =
                    g.Average(product => product.Field<Decimal>("ListPrice"))
            };

LINQ 的另一種表示方法

2008 MVC (Modual View Controller) 架構介紹

http://msdn.microsoft.com/zh-tw/magazine/cc337884.aspx#S2

MVC至今已推廣三年,由MVC 發展至 MVC3

未來的發展實令人值得期待,開創Web高速的時代

from:http://blog.darkthread.net/blogs/darkthreadtw/archive/2009/12/15/5775.aspx

如果你使用的平台是.NET 3.5，在操作XML文件時會有三種選擇: LINQ to XML, LINQ to XML with XPath以及傳統的XmlDocument。既然有三種選擇，排除個人主觀偏好，想知道哪一種做法的效能最好呢?

之前有個迷思，一直覺得LINQ表達方式友善，理論上會付出效能上的代價(正所謂有一好沒兩好)。所以有時針對複雜的元素查詢，我會using System.Xml.XPath，然後改用XPathSelectElements()查詢，直到無意間發現了一篇談LINQ to XML與XPath Benchmark的文章，才發現我錯了。該文作者試了一個120,000筆資料, 54MB大小的XML檔案，LINQ to XML用LINQ語法查詢，竟比叫用XPathSelectElements()快了五倍!!

我自己也做了一個測試，產生一個36M大小20,000 * 100個Node的XML文件，分別用LINQ to XML, XPathSelectElements及XmlDocument.SelectNodes去查詢同樣條件，統計Node數。依我的測試結果，也驗證了LINQ to XML確實比XPathSelectElements來得快，至於XmlDocument，我們就忘了它吧...

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Xml.Linq;
using System.Diagnostics;
using System.Xml.XPath;
using System.Xml;
 
namespace TestXmlPerformance
{
    class Program
    {
        static void GenSampleXml()
        {
            StringBuilder sb = new StringBuilder();
            sb.Append("<root>");
            Random rnd = new Random();
            for (int i = 0; i < 20000; i++)
            {
                sb.AppendFormat("<pack id=\"{0}\">", i);
                for (int j = 0; j < 100; j++)
                    sb.AppendFormat("<item model=\"{0}\" />",
                        rnd.Next(20));
                sb.Append("</pack>");
            }
            sb.Append("</root>");
            File.WriteAllText(".\\Sample.xml", sb.ToString());
        }
 
        static void Main(string[] args)
        {
            //GenSampleXml();
            {
                Stopwatch sw = new Stopwatch();
                sw.Start();
                XDocument xd = XDocument.Load(".\\Sample.xml");
                var q = from o in xd.Descendants("item")
                        where o.Attribute("model").Value == "7"
                        select o;
                Console.WriteLine(q.Count());
                sw.Stop();
                Console.WriteLine("Test 1: {0}ms",
                    sw.ElapsedMilliseconds);
            }
 
            {
                Stopwatch sw = new Stopwatch();
                sw.Start();
                XDocument xd = XDocument.Load(".\\Sample.xml");
                Console.WriteLine(
                    xd.XPathSelectElements("root/pack/item[@model='7']")
                    .Count()
                );
                sw.Stop();
                Console.WriteLine("Test 2: {0}ms",
                    sw.ElapsedMilliseconds);
            }
 
            {
                Stopwatch sw = new Stopwatch();
                sw.Start();
                XmlDocument xd = new XmlDocument();
                xd.Load(".\\Sample.xml");
                Console.WriteLine(
                    xd.DocumentElement
                    .SelectNodes("pack/item[@model='7']").Count
                );
                sw.Stop();
                Console.WriteLine("Test 3: {0}ms",
                    sw.ElapsedMilliseconds);
            }
 
            Console.Read();
        }
    }
}

行動裝置各軟體加持

http://lifeorganizers.com/

http://www.evernote.com/about/intl/zh-tw/download/

http://www.toodledo.com/info/details.php

全國四季花曆

from http://www.dotblogs.com.tw/pin0513/archive/2010/03/08/13931.aspx

 1: public class Singleton{

 2: //透用一個靜態變數記錄實體

 3: private static Singleton uniqueInstance;

 4: //建構式的啦

在這邊分享自己常用的快速鍵，也記錄一下讓自己不小心忘記的時候可以查一下

移至定義

F12

在方法定義和調用之點切换

Ctrl + Shift + 7(8)

在已安裝ASP.NET MVC的機器找到以下檔案(32位元OS則在C:\Program Files (x86)\Microsoft ASP.NET目錄)，把它們Copy到部署機器的BIN目錄下就OK囉! (注意: 主機IIS要安裝SP.NET 4.0，網站也要設定使用ASP.NET 4.0)

C:\Program Files (x86)\Microsoft ASP.NET\ASP.NET Web Pages\v1.0\Assemblies

• System.Web.Helpers.dll
• System.Web.Razor.dll
• System.Web.WebPages.dll
• System.Web.WebPages.Razor.dll
• System.Web.WebPages.Deployment.dll
• Microsoft.Web.Infrastructure.dll

C:\Program Files (x86)\Microsoft ASP.NET\ASP.NET MVC 3\Assemblies

• System.Web.Mvc.dll
  (Phil文章中提到的System.Web.Abstractions.dll, System.Web.Extensions.dll, System.Web.Routing.dll在.NET Framework 4.0已屬內建)