问题描述

可能重复:
强密码正则表达式
需要正则表达式以获得密码强度?

我只是想知道在字符串中搜索某些条件(具体来说是密码强度)的最佳方法是什么.

I was just wondering what the best way to search a string for certain criteria (password strength to be specific) could be accomplished.

到目前为止，我有一个简单的:

So far I have a simple:

if(password.Length <= 7)
    {
        errorMessage = "Your password must be at least 8 characters.";
    }

我希望能够检查大写字母，但我不确定方法或程序是什么.我试过谷歌搜索，搜索网站:http://msdn.microsoft.com，并搜索我的索引C# 书(C# Programming 3E，Barbara Doyle 着)，但我似乎找不到.

I would like to be able to check for capital letters, but I am not sure what the method or procedure is. I have tried Googling, searching the website: http://msdn.microsoft.com, and searching the index of my C# book (C# Programming 3E, by Barbara Doyle), but I can't seem to find any.

我知道我可以试试这个...:

I know I could try this...:

foreach(char c in password)
    {
        if(c!='A' || c!='B' || c!='C' || c!='D' ..... || c!='Z')
        {
            errorMessage = "Your password must contain at least one capital letter";
        }
    }

...但这将非常草率，并且必须加倍才能检查至少一个小写字母.我确信有更好的方法来做到这一点，或者至少是我上面显示的方法的简写.

...But that would be extremely sloppy, and would have to be doubled to check for at least one lowercase letter. I am sure there is a better way to do this, or at least shorthand for the method I have shown above.

另外，我可能会决定检查特殊字符的密码(在上面的示例中似乎比使用大小写字母更容易，所以我可以只将它用于特殊字符，如果我决定让它们成为必要的话).如果有一种简单(或适当)的方法可以做到这一点，我也很想拥有这些知识.

Also, I may decide to check the password for special characters (seems easier to do in the example above than with upper and lower case letters, so I may just use that for special characters, should I decide to make them necessary). If there is an easy (or proper) way to do that, I would love to have that knowledge, as well.

无论如何，非常感谢您提供的任何帮助.

Anyway, thank you so much for any help anyone can give.

推荐答案

我不能相信，因为我从 这里

I can't take the credit, as I stole this from here

using System.Text;
using System.Text.RegularExpressions;

  public enum PasswordScore
  {
    Blank = 0,
    VeryWeak = 1,
    Weak = 2,
    Medium = 3,
    Strong = 4,
    VeryStrong = 5
  }

  public class PasswordAdvisor
  {
    public static PasswordScore CheckStrength(string password)
    {
      int score = 0;

      if (password.Length < 1)
        return PasswordScore.Blank;
      if (password.Length < 4)
        return PasswordScore.VeryWeak;

      if (password.Length >= 8)
        score++;
      if (password.Length >= 12)
        score++;
      if (Regex.Match(password, @"/d+/", RegexOptions.ECMAScript).Success)
        score++;
      if (Regex.Match(password, @"/[a-z]/", RegexOptions.ECMAScript).Success &&
        Regex.Match(password, @"/[A-Z]/", RegexOptions.ECMAScript).Success)
        score++;
      if (Regex.Match(password, @"/.[!,@,#,$,%,^,&,*,?,_,~,-,£,(,)]/", RegexOptions.ECMAScript).Success)
        score++;

      return (PasswordScore)score;
    }
  }

注意使用正则表达式检查大写字符.这似乎是一种不错的方法，因为它会检查长度、大小写字符的使用、数字和特殊字符.

Note the use of regex for checking for upper case characters. This appears to be a decent approach, as it checks length, use of upper and lower case characters, numeric digits and special characters.

** 更新**

我知道问题现在已经结束，但我可以添加更多解释让 VoidKing 理解一些概念.

I know the question is now closed, but I can add more explanation for VoidKing to understand some of the concepts.

从 CheckStrength 方法返回的 PasswordScore 可用作代码中下一步操作的条件.

A PasswordScore is returned from the CheckStrength method, which can be used as the condition for what to do next in your code.

以下是如何使用上述代码的未经测试的演示:

Here's an untested demo of how the above code could be used:

String password = "MyDummy_Password"; // Substitute with the user input string
PasswordScore passwordStrengthScore = PasswordAdvisor.CheckStrength(password);

switch (passwordStrengthScore) {
    case PasswordScore.Blank:
    case PasswordScore.VeryWeak:
    case PasswordScore.Weak:
            // Show an error message to the user
            break;
    case PasswordScore.Medium:
    case PasswordScore.Strong:
    case PasswordScore.VeryStrong:
           // Password deemed strong enough, allow user to be added to database etc
           break;
}

在这种情况下，枚举被用作将密码强度分类为人类可读组的一种方法.保持代码整洁，并让代码中发生的事情一目了然.

Enums are used in this case as a means of classifying the strength of the password into human-readable groups. Keeps the code clean, and makes it obvious what is going on in the code.

关于 Regex 的使用，如果您不熟悉它们的概念以及如何以及何时使用它们，我建议您进行一些研究，因为这些对于检查字符串中的模式在许多不同的场景中都很有用.也许从这里开始.

Regarding the use of Regex's, if you're unfamiliar with the concept of them and how and when to use them, I suggest doing some research as these can be useful in many different scenarios for checking for patterns in strings. Perhaps start here.

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