關於C# 的高效隨機字串 (轉)

關於C# 的高效隨機字串 (轉)[@more@]

使用RNGCryptoServiceProvr 做種，可以在一秒內產生的隨機數重複率非常的低，對於以往使用時間做種的方法是個升級，程式碼如下：

using System;
using System.Security.Cryptography;

namespace ArLi.CommonPrj
{
 ///

 /// 隨機密碼
 ///

 public sealed class RanStr {

 public const string myVersion = "1.2";

 /********
 *  Const and Function
 *  ********/

 private static readonly int defaultLength = 8;

 private static int GetNewSeed(){
 byte[] rnytes = 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 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 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);
 }
 }
}