关于C# 的高效随机字符串

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
{
///

1<summary>   
2/// 随机密码   
3/// </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);
}
}
}