标签： c#

C#中根据Enum的值获取对应的名称

public enum OrderStateEnum
{
    未发货 = 1 ,
    已发货 = 2 ,
    交易成功 = 3
}

意思就是，根据1，2，3获取对应的key（如”未发货”）

代码如下：

this.txtState.Text = Enum.Parse(typeof(OrderStateEnum), "1",  true).ToString();

C#下载网页图片

static void Main(string [] args)
{
    string url1 = "http://my.oschina.net/js/ke/plugins/emoticons/{0}.gif" ;
    for(int i=0; i<135; i++)
    {
        string url = string.Format(url1, i);
        WebRequest request = WebRequest .Create(url);
        WebResponse response = request.GetResponse();
        Stream reader = response.GetResponseStream();
        FileStream writer = new FileStream (@"E:\临时测试\ConsoleApplication2\新建文件夹\" + i.ToString() + ".gif", FileMode.OpenOrCreate, FileAccess.Write);
        byte[] buff = new byte[512];
        int c = 0; //实际读取的字节数
        while ((c = reader.Read(buff, 0, buff.Length)) > 0)
        {
            writer.Write(buff, 0, c);
        }
        writer.Close();
        writer.Dispose();
        reader.Close();
        reader.Dispose();
        response.Close();
    }
    Console.WriteLine( "下载完成.." );
}

C# Http GET 和POST HttpClient HttpHelper

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading.Tasks;
namespace alimama
{
    class HttpHelper
    {
        private static CookieContainer cookieContainer = new CookieContainer();
        private static int _timeOut = 1000 * 30; // 30秒超时  默认值是 100,000 毫秒（100 秒）
        static public string HttpGet(string url, string referer = "")
        {
            HttpWebRequest httpWebRequest = null;
            HttpWebResponse httpWebResponse = null;
            httpWebRequest = (HttpWebRequest)HttpWebRequest.Create(url);
            httpWebRequest.CookieContainer = cookieContainer;
            httpWebRequest.Method = "GET";
            httpWebRequest.ServicePoint.ConnectionLimit = int.MaxValue;
            if (!string.IsNullOrEmpty(referer))
            {
                httpWebRequest.Referer = referer;
            }
            //httpWebRequest.Host = Host;
            httpWebRequest.UserAgent = "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.63 Safari/537.36";
            httpWebRequest.KeepAlive = true;
            httpWebRequest.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";
            httpWebRequest.ServicePoint.Expect100Continue = false;
            httpWebRequest.Timeout = _timeOut; //默认值是 100,000 毫秒（100 秒）
            httpWebResponse = (HttpWebResponse)httpWebRequest.GetResponse();
            Stream responseStream = httpWebResponse.GetResponseStream();
            StreamReader streamReader = new StreamReader(responseStream, Encoding.UTF8);
            string html = streamReader.ReadToEnd();
            streamReader.Close();
            responseStream.Close();
            httpWebRequest.Abort();
            httpWebResponse.Close();
            return html;
        }
        static public string HttpPost(string url, string postData, string referer = "")
        {
            HttpWebRequest httpWebRequest = null;
            HttpWebResponse httpWebResponse = null;
            httpWebRequest = (HttpWebRequest)HttpWebRequest.Create(url);
            httpWebRequest.CookieContainer = cookieContainer;
            httpWebRequest.Method = "POST";
            httpWebRequest.ServicePoint.ConnectionLimit = int.MaxValue;
            if (!string.IsNullOrEmpty(referer))
            {
                httpWebRequest.Referer = referer;
            }
            //httpWebRequest.Host = Host;
            httpWebRequest.UserAgent = "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.63 Safari/537.36";
            httpWebRequest.KeepAlive = true;
            httpWebRequest.ContentType = "application/x-www-form-urlencoded; charset=UTF-8";
            httpWebRequest.ServicePoint.Expect100Continue = false;
            httpWebRequest.Timeout = _timeOut; //默认值是 100,000 毫秒（100 秒）
            byte[] byteArray = Encoding.UTF8.GetBytes(postData); //转化
            httpWebRequest.ContentLength = byteArray.Length;
            Stream newStream = httpWebRequest.GetRequestStream();
            newStream.Write(byteArray, 0, byteArray.Length); //写入参数
            newStream.Close();
            httpWebResponse = (HttpWebResponse)httpWebRequest.GetResponse();
            Stream responseStream = httpWebResponse.GetResponseStream();
            StreamReader streamReader = new StreamReader(responseStream, Encoding.UTF8);
            string html = streamReader.ReadToEnd();
            streamReader.Close();
            responseStream.Close();
            httpWebRequest.Abort();
            httpWebResponse.Close();
            return html;
        }
        static public void Download(string url, string savePath)
        {
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            request.CookieContainer = cookieContainer;
            WebResponse response = request.GetResponse();
            Stream reader = response.GetResponseStream();
            FileStream writer = new FileStream(savePath, FileMode.OpenOrCreate, FileAccess.Write);
            byte[] buff = new byte[512];
            int c = 0; //实际读取的字节数
            while ((c = reader.Read(buff, 0, buff.Length)) > 0)
            {
                writer.Write(buff, 0, c);
            }
            writer.Close();
            writer.Dispose();
            reader.Close();
            reader.Dispose();
            response.Close();
        }
    }
}

C#中，让线程挂起。不能使用Thead.Suspend(), 这个函数在.NET中已经被否决了，具体原因没有深入研究。微软推荐使用System.Threading中的函数，比如Monitor, Mutex, Event等。

在QQ好友空间访客提取的项目中我使用了ManualResetEvent这个Event类，具体用法如下:

类字段定义:

private ManualResetEvent _event = new ManualResetEvent (true ); //线程事件
private bool _pause = false; //线程是否暂停

工作线程函数中:

if (_pause)
{
     SetStatus( "已暂停");
}
_event.WaitOne();

暂停函数中:

SetStatus("暂停中...");
_event.Reset();
_pause = true;

恢复函数中:

if (_pause)
{
     //to resume thread
     _event.Set();
     _pause = false;

     return;
}

C#合并数组

public string[] MergerArray(string[] First, string[] Second)
{
    string[] result = new string[First.Length + Second.Length];
    First.CopyTo(result, 0);
    Second.CopyTo(result, First.Length);
    return result;
}

泛型版本

public T[] MergerArray<T>(T[] First,T[] Second)
{
    T[] result =new T[First.Length + Second.Length];
    First.CopyTo(result, 0);
    Second.CopyTo(result, First.Length);
    return result;
}

合并多个数组

/// <summary>
/// 连接多个数组
/// </summary>
/// <typeparam name="T">数组数据类型</typeparam>
/// <param name="source">源数组</param>
/// <param name="arrays">被连接的多个数组</param>
/// <returns></returns>
public static T[] Concat<T>(this T[] source, params T[][] arrays)
{
    if (source == null)
    {
        throw new ArgumentNullException("source");
    }


    var length = source.Length + arrays.Sum(array => array != null ? array.Length : 0);
    var result = new T[length];
    length = source.Length;
    Array.Copy(source, 0, result, 0, source.Length);
    foreach (var array in arrays)
    {
        if (array != null)
        {
            Array.Copy(array, 0, result, length, array.Length);
            length += array.Length;
        }
    }
    return result;
}