关于C# 的高效随机字符串

王朝c#·作者佚名  2006-01-08
窄屏简体版  字體: |||超大  

使用RNGCryptoServiceProvider 做种,可以在一秒内产生的随机数重复率非常的低,对于以往使用时间做种的方法是个升级,代码如下:

using System;

using System.Security.Cryptography;

namespace ArLi.CommonPrj

{

/// <summary>

/// 随机密码

/// </summary>

public sealed class RandomStr {

public const string myVersion = "1.2";

/********

* Const and Function

* ********/

private static readonly int defaultLength = 8;

private static int GetNewSeed(){

byte[] rndBytes = new byte[4];

RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();

rng.GetBytes(rndBytes);

return BitConverter.ToInt32(rndBytes,0);

}

/********

* getRndCode of all char .

* ********/

private static string BuildRndCodeAll(int strLen) {

System.Random RandomObj = new System.Random(GetNewSeed());

string buildRndCodeReturn = null;

for(int i=0; i<strLen; i++) {

buildRndCodeReturn += (char)RandomObj.Next(33,125);

}

return buildRndCodeReturn;

}

public static string GetRndStrOfAll() {

return BuildRndCodeAll(defaultLength);

}

public static string GetRndStrOfAll(int LenOf) {

return BuildRndCodeAll(LenOf);

}

/********

* getRndCode of only .

* ********/

private static string sCharLow = "abcdefghijklmnopqrstuvwxyz";

private static string sCharUpp = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

private static string sNumber = "0123456789";

private static string BuildRndCodeOnly(string StrOf,int strLen) {

System.Random RandomObj = new System.Random(GetNewSeed());

string buildRndCodeReturn = null;

for(int i=0; i<strLen; i++) {

buildRndCodeReturn += StrOf.Substring(RandomObj.Next(0,StrOf.Length-1),1);

}

return buildRndCodeReturn;

}

public static string GetRndStrOnlyFor() {

return BuildRndCodeOnly(sCharLow + sNumber,defaultLength);

}

public static string GetRndStrOnlyFor(int LenOf) {

return BuildRndCodeOnly(sCharLow + sNumber,LenOf);

}

public static string GetRndStrOnlyFor(bool bUseUpper,bool bUseNumber) {

string strTmp = sCharLow;

if (bUseUpper) strTmp += sCharUpp;

if (bUseNumber) strTmp += sNumber;

return BuildRndCodeOnly(strTmp,defaultLength);

}

public static string GetRndStrOnlyFor(int LenOf,bool bUseUpper,bool bUseNumber) {

string strTmp = sCharLow;

if (bUseUpper) strTmp += sCharUpp;

if (bUseNumber) strTmp += sNumber;

return BuildRndCodeOnly(strTmp,LenOf);

}

}

}

 
 
 
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