Question

我试图申请的政策是它必须是3个字符长，它必须包括小写字母，大写字母和任何顺序的数字。我试图用它作为一种方法来读取用户设置的密码进行分配。我尽可能多地写出了消除错误但我无法找到应用所述策略的方法。这是我到目前为止...任何帮助将不胜感激

    private static string readPass() { //readpass method to read in password of 1 lower case, 1 upper case & 1 number


        bool validInput = true;
        char letterUserInput;                                           //letter from string
        int asciiCodeLetter;                                            //number code for letter
        string userInput;

        do {
            validInput = true;
            userInput = Console.ReadLine();
        try {

                if (userInput.Length < 1) {
                    validInput = false;
                    Console.WriteLine("You have just pressed Enter Please Enter a valid Password");
                }                      //if check length

                else if (userInput.Length > 1 && userInput.Length < 3) {
                    validInput = false;
                    Console.WriteLine("Password Is Too Short. Please Enter Valid Password");
                }                                                       //if check length too short

                else if (userInput.Length > 3)
                {
                    validInput = false;
                    Console.WriteLine("Password Is Too Long. Please Enter A Valid Password");
                }                                                       //if check length too short

                for (int i = 0; i < userInput.Length; i++)              //take each letter in turn from string
                {
                    letterUserInput = userInput[i];
                    asciiCodeLetter = Convert.ToInt16(letterUserInput);
                    if (asciiCodeLetter < 48 || asciiCodeLetter > 57)
                    {
                        validInput = false;
                        Console.WriteLine("You have used an invalid character.\n Password Must Contain 1 Upper Case, 1 Lower Case letter and 1 Number)");
                    }                                                    //character check with ASCII
                }
            }
            catch
            {
                validInput = false;
                Console.WriteLine("An unspecified error has occured");
            }                                                           //catch

            if (validInput == false) Console.Write("Invalid Password. Please Enter Again = ");

        } while (validInput == false);                                  // do. repeat entry if invalid

        return userInput;
    }

Answer 1

对此的一些伪代码可能是：

String candidatePwd = textboxPwd.Text.Trim();
Boolean validPwd = IsValidPassword(candidatePwd);

private bool IsValidPassword(String candidate)
{
    return ((candidate.Length == 3) &&
            (ContainsOneUppercaseLetter(candidate)) &&
            (ContainsOneLowerCaseLetter(candidate)) &&
            (ContainsOneNumber(candidate)));
}

private bool ContainsOneUppercaseLetter(String candidate)
{
   // search for an uppercase letter; if one found, return true
}

private bool ContainsOneLowercaseLetter(String candidate)
{
   // search for a lowercase letter; if one found, return true
}

private bool ContainsOneUppercaseLetter(String candidate)
{
   // search for a number; if one found, return true
}

实际的实施留给你。

Answer 2

您可以使用正则表达式：

var input = Console.ReadLine();
var regex = new System.Text.RegularExpressions.Regex("^([0-9][a-z][A-Z]|[0-9][A-Z][a-z]|[a-z][0-9][A-Z]|[a-z][A-Z][0-9]|[A-Z][a-z][0-9]|[A-Z][0-9][a-z])$");
validInput = input != null && regex.IsMatch(input);

我确信有更多花哨的正则表达式。但如果您不熟悉正则表达式，那么这就足以理解它了。

修改

如果您想要更有趣的东西，可以使用以下正则表达式：

 var input = Console.ReadLine();
 var regex = new System.Text.RegularExpressions.Regex(@"^(?=.*\d)(?=.*[a-z])(?=.*[A-Z]).{3}$");
 validInput = input != null && regex.IsMatch(input);

Answer 3

对于3个字符 - 只需将用户写的密码保存为字符串，然后检查它的长度。如果是大写的话，我会转换ASCII码上的每个字符，然后检查是否有任何代码等于所有大写字母的代码。要检查是否有号码，请使用类似的内容检查密码的每个字符

int n; bool isNumeric = int.TryParse（“123”，out n）;

希望这会有所帮助。

Answer 4

您可以使用正则表达式：

^。（？= {3}）（？=。 \ d）（？= [AZ]）（？=。 [AZ] ）。* $

并简化您的代码：

if(!Regex.IsMatch(userInput, "^.*(?=.{7,})(?=.*\d)(?=.*[a-z])(?=.*[A-Z]).*$")
  Console.WriteLine("The password has to be 3 characters long, and must include a lower case letter, an upper case letter, and a number");

我需要为具有一些策略的控制台应用程序编写一个读取字符串方法

4 个答案:

修改