Question

我知道有很多这些线程，但我是vb.net的新手但我无法编辑给出的内容来制作我真正想要的东西所以我想要一个函数，它将生成随机字符串，每个字符串包含15-32个字符，每个字符将包含以下字符（不是所有字符串都在同一个字符串中，但其中一些字符串）： A-Z A-Z 0-9 这是我到目前为止的代码

Functon RandomString()
    Dim s As String = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
    Dim r As New Random
    Dim sb As New StringBuilder
    For i As Integer = 1 To 8
        Dim idx As Integer = r.Next(0, 35)
        sb.Append(s.Substring(idx, 1))
    Next
    return sb.ToString()
End Function

Answer 1

更改字符串以包含a-z字符：

Dim s As String = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"

更改循环以创建随机数字符：

Dim cnt As Integer = r.Next(15, 33)
For i As Integer = 1 To cnt

请注意，Next方法的上边界是独占的，因此Next(15, 33)会为您提供一个范围为15到32的值。

使用字符串的长度从中挑选一个字符：

Dim idx As Integer = r.Next(0, s.Length)

由于您要创建随机字符串而不是单个随机字符串，因此不应在函数内创建随机数生成器。如果你将函数调用两次太近，你最终会得到相同的随机字符串，因为随机生成器是使用系统时钟播种的。因此，您应该将随机生成器发送到函数：

Function RandomString(r As Random)

所以，总而言之：

Function RandomString(r As Random)
  Dim s As String = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
  Dim sb As New StringBuilder
  Dim cnt As Integer = r.Next(15, 33)
  For i As Integer = 1 To cnt
    Dim idx As Integer = r.Next(0, s.Length)
    sb.Append(s.Substring(idx, 1))
  Next
  return sb.ToString()
End Function

用法示例：

Dim r As New Random
Dim strings As New List<string>()
For i As Integer = 1 To 10
  strings.Add(RandomString(r))
Next

Answer 2

尝试这样的事情： -

stringToReturn&= Guid.NewGuid.ToString().replace("-","")

您还可以查看this： -

Sub Main()
        Dim KeyGen As RandomKeyGenerator
        Dim NumKeys As Integer
        Dim i_Keys As Integer
        Dim RandomKey As String

        ''' MODIFY THIS TO GET MORE KEYS    - LAITH - 27/07/2005 22:48:30 -
        NumKeys = 20

        KeyGen = New RandomKeyGenerator
        KeyGen.KeyLetters = "abcdefghijklmnopqrstuvwxyz"
        KeyGen.KeyNumbers = "0123456789"
        KeyGen.KeyChars = 12
        For i_Keys = 1 To NumKeys
            RandomKey = KeyGen.Generate()
            Console.WriteLine(RandomKey)
        Next
        Console.WriteLine("Press any key to exit...")
        Console.Read()
    End Sub

Answer 3

使用您的功能作为指导，我将其修改为：

随机化长度（在minChar和maxCharacters之间）
随机化每次产生的字符串（使用静态随机）

代码：

Function RandomString(minCharacters As Integer, maxCharacters As Integer)
    Dim s As String = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
    Static r As New Random
    Dim chactersInString As Integer = r.Next(minCharacters, maxCharacters)
    Dim sb As New StringBuilder
    For i As Integer = 1 To chactersInString
        Dim idx As Integer = r.Next(0, s.Length)
        sb.Append(s.Substring(idx, 1))
    Next
    Return sb.ToString()
End Function

Answer 4

您需要将行For i As Integer = 1 To 8更改为For i As Integer = 1 To ?在哪里？是字符串应该是多长的字符数。这会改变它重复下面代码的次数，因此会在字符串中附加更多字符。

    Dim idx As Integer = r.Next(0, 35)
    sb.Append(s.Substring(idx, 1))

Answer 5

我的$ .02

Dim prng As New Random
Const minCH As Integer = 15 'minimum chars in random string
Const maxCH As Integer = 35 'maximum chars in random string

'valid chars in random string
Const randCH As String = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"

Private Function RandomString() As String
    Dim sb As New System.Text.StringBuilder
    For i As Integer = 1 To prng.Next(minCH, maxCH + 1)
        sb.Append(randCH.Substring(prng.Next(0, randCH.Length), 1))
    Next
    Return sb.ToString()
End Function

Answer 6

请注意

r.Next(0, 35)

倾向于挂起并显示相同的结果不确定whay;更好用

CInt(Math.Ceiling(Rnd() * N)) + 1

在此处查看Random integer in VB.NET

Answer 7

试试这个：

Private Function RandomString(ByRef Length As String) As String
    Dim str As String = Nothing
    Dim rnd As New Random
    For i As Integer = 0 To Length
        Dim chrInt As Integer = 0
        Do
            chrInt = rnd.Next(30, 122)
            If (chrInt >= 48 And chrInt <= 57) Or (chrInt >= 65 And chrInt <= 90) Or (chrInt >= 97 And chrInt <= 122) Then
                Exit Do
            End If
        Loop
        str &= Chr(chrInt)
    Next
    Return str
End Function

Answer 8

我根据自己的需要增强了Nathan Koop的功能，并认为我会分享。

我添加了：

能够在随机字符串中添加前置和附加文本
能够选择允许的字符（字母）的大小写
可以选择在允许的字符中包含/排除数字

注意：如果严格寻找精确长度的字符串，同时还要添加前置/附加字符串，则需要进行处理；我没有处理任何逻辑。

用法示例：

' Straight call for a random string of 20 characters
' All Caps + Numbers
String_Random(20, 20, String.Empty, String.Empty, 1, True)

' Call for a 30 char string with prepended string
' Lowercase, no numbers
String_Random(30, 30, "Hey_Now_", String.Empty, 2, False)

' Call for a 15 char string with appended string
' Case insensitive + Numbers
String_Random(15, 15, String.Empty, "_howdy", 3, True)

。

Public Function String_Random(
    intMinLength As Integer,
    intMaxLength As Integer,
    strPrepend As String,
    strAppend As String,
    intCase As Integer,
    bIncludeDigits As Boolean) As String

    ' Allowed characters variable
    Dim s As String = String.Empty

    ' Set the variable to user's choice of allowed characters
    Select Case intCase

        Case 1

            ' Uppercase
            s  = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"

        Case 2

            ' Lowercase
            s = "abcdefghijklmnopqrstuvwxyz"                

        Case Else

            ' Case Insensitive + Numbers
            s  = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz" 

    End Select

    ' Add numbers to the allowed characters if user chose so
    If bIncludeDigits = True Then s &= "0123456789"

    Static r As New Random

    Dim chactersInString As Integer = r.Next(intMinLength, intMaxLength)
    Dim sb As New StringBuilder

    ' Add the prepend string if one was passed
    If String.IsNullOrEmpty(strPrepend) = False Then sb.Append(strPrepend)

    For i As Integer = 1 To chactersInString

        Dim idx As Integer = r.Next(0, s.Length)

        sb.Append(s.Substring(idx, 1))

    Next

    ' Add the append string if one was passed
    If String.IsNullOrEmpty(strAppend) = False Then sb.Append(strAppend)

    Return sb.ToString()

End Function

生成随机字符串

8 个答案: