Module Module1
Dim database As New Dictionary(Of String, String)
Dim ulist As New List(Of String)
Dim plist As New List(Of String)
Dim newname As String
Dim passw As String
Sub main()
menu() '
End Sub
Sub menu()
Console.WriteLine("type 1, 2 or 3")
Console.WriteLine("1 : create a new account")
Console.WriteLine("2: log in ")
Console.WriteLine("3 : quit program")
Dim choice As String
choice = Console.ReadLine()
If choice = "1" Then
create()
ElseIf choice = "2" Then
login()
ElseIf choice = "3" Then
Console.WriteLine("quitting...")
Console.Clear()
End If
End Sub
Sub login()
Dim unamever As String
Dim passwvari
Dim veri3 As Boolean = False
While veri3 = False
Console.WriteLine("please enter you username")
unamever = Console.ReadLine()
If ulist.Contains(unamever) Then
Console.WriteLine("please enter your password : ")
passwvari = Console.ReadLine()
If plist.Contains(passwvari) Then
Console.WriteLine("logging you in...")
veri3 = True
Else
Console.WriteLine("password incorrect try again")
veri3 = False
End If
Else
Console.WriteLine("username not registered try again")
veri3 = False
End If
End While
End Sub
Sub create()
Dim veri As Boolean = False
Dim attempts As Integer = 1
Do Until veri = True
Console.WriteLine("enter a new username")
newname = Console.ReadLine()
If ulist.Contains(newname) Then
Console.WriteLine("that username is already taken, try again")
attempts = attempts + 1
veri = False
Else
ulist.Add(newname)
Console.WriteLine("your new username has been stored")
notused()
veri = True
database.Add(newname, passw)
Console.WriteLine("succes you have made an account you username :" & newname & " and password: " & passw)
FileOpen(1, "C:UsersiivixOneDriveDocumentsA LEVELpassws.txt", OpenMode.Output)
PrintLine(1, newname & passw)
End If
If attempts > 4 Then
Console.WriteLine("you have had more than 3 tries, BYE")
Console.Clear()
End If
Loop
End Sub
Sub notused()
Dim veri2 As Boolean = False
While veri2 = False
Console.WriteLine("create a password " & newname)
passw = Console.ReadLine
Dim passwlen = Len(passw)
If passwlen > 12 Then
Console.WriteLine("your password has been stored ")
plist.Add(passw)
veri2 = True
Else
Console.WriteLine("try again password must be greater than 12 characters")
veri2 = False
End If
End While
End Sub
End Module
这个代码是一个登录系统，我是一个vb初学者，这是我的代码到目前为止，我遇到了一个问题:为什么不被存储的用户名，当我尝试登录以后，我怎么能解决这个问题?我希望用户能够在创建帐户时重新登录另一个问题是，将用户名和密码写入文本文件时新用户名覆盖最后一个，我希望用户名与密码'
一起连续列出- 顺便说一句，这不是家庭作业，这是初学者的编程挑战
我已经更新了你的代码，使用。net方法而不是过时的VB6方法。我使LoginPatha模块级变量，所以它可以看到我在模块中的所有方法。我用的是一个Dictionary，而不是2个List(Of String)。这样，用户名就是值中的密钥和密码。查找字典非常快。
要做的第一件事是读取文件并填充字典。如果该文件不存在，则通知用户。
Create方法会随着Dictionary的使用而发生一些变化。我使用。netFile类来写入文本文件。
File.AppendAllLines(LoginPath, {$"{newname},{passw}"})
这是一个非常聪明的方法。如果文件不存在，它就创建它。它打开文件，写入文件，然后关闭文件。第一个参数是路径。第二个参数是要写入文件的内容，一个String数组。注意，方法名以AllLines结尾，是复数形式。外括号表示这是一个数组。这个数组只有一个元素。我使用了一个内插字符串，由字符串前面的$表示。然后可以直接将变量插入用大括号括起来的字符串中。逗号是字符串中的字面量。当字符串被分成名称和密码时，我们使用逗号作为分隔符。
Private LoginPath As String = "C:UsersiivixOneDriveDocumentsA LEVELpassws.txt"
Private LoginDict As New Dictionary(Of String, String)
Sub Main()
ReadLoginFileAndFillDictionary()
menu()
Console.ReadKey()
End Sub
Private Sub Menu() 'Names of Subs, Functions etc. should begin with capital letters
Console.WriteLine("type 1, 2 or 3")
Console.WriteLine("1 : create a new account")
Console.WriteLine("2: log in ")
Console.WriteLine("3 : quit program")
Dim choice As String
choice = Console.ReadLine()
If choice = "1" Then
Create()
ElseIf choice = "2" Then
Login()
ElseIf choice = "3" Then
Console.WriteLine("quitting...")
Environment.Exit(0)
End If
End Sub
Private Sub Create()
Dim veri As Boolean 'Default value is False, value types initialize automatically
Dim attempts As Integer
Dim newname As String = ""
Dim passw As String = ""
Do Until veri = True
Console.WriteLine("enter a new username")
newname = Console.ReadLine()
If LoginDict.ContainsKey(newname) Then 'Searches the Keys in the Dictionary and returns True or False
Console.WriteLine("that username is already taken, try again")
attempts += 1 'new syntax for updating the value of a variable, saves a bit of typing
Else
veri = True
End If
If attempts > 4 Then
Console.WriteLine("you have had more than 3 tries, BYE")
Console.Clear()
Environment.Exit(0) 'To end the application
End If
Loop
veri = False 'You can use the same variable just reset its value
While veri = False
Console.WriteLine("create a password " & newname)
passw = Console.ReadLine
Dim passwlen = passw.Length 'Don't use the old VB6 Len
If passwlen > 12 Then
LoginDict.Add(newname, passw) 'Here is where the new user is added to the Dictionary
veri = True
Else
Console.WriteLine("try again, password must be greater than 12 characters")
End If
End While
Console.WriteLine("your new username and password have been stored")
Console.WriteLine("succes, you have made an account your username :" & newname & " and password: " & passw)
File.AppendAllLines(LoginPath, {$"{newname},{passw}"}) 'Adds the new user to the text file
End Sub
Private Sub Login()
Dim unamever As String = ""
Dim passwvari As String = ""
Dim veri As Boolean 'You don't need a different name for a variable in a another method.
While veri = False
Console.WriteLine("please enter you username")
unamever = Console.ReadLine()
If LoginDict.ContainsKey(unamever) Then 'Searches the Keys in the Dictionary and returns True or False
passwvari = LoginDict(unamever) 'Gets the value associated with the username
Console.WriteLine("please enter your password : ")
If passwvari = Console.ReadLine Then 'Compares the value found in the Dictionary to the string entered by the user.
Console.WriteLine("logging you in...")
veri = True
Else
Console.WriteLine("password incorrect, try again")
End If
Else
Console.WriteLine("username not registered, try again")
End If
End While
End Sub
Private Sub ReadLoginFileAndFillDictionary()
If File.Exists(LoginPath) Then
Dim lines = File.ReadAllLines(LoginPath) 'Read the file into an array of lines
For Each line In lines
Dim splits = line.Split(","c) 'Split each line by the comma into an array of 2 strings
LoginDict.Add(splits(0), splits(1)) 'The first element is the username and the second element is the password.
Next
Else
Console.WriteLine("There are currently no registered users. Please begin with Option 1.")
End If
End Sub
在实际应用程序中，您将NEVER以明文形式存储密码。