生成随机字符串

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信息来做我真正想要的所以我想要一个能生成随机字符串的函数,每个字符串包含15-32个字符并且它们中的每一个都有以下字符(不是全部在同一个字符串中,而是其中一些字符串):AZ az 0-9这里是我的代码到目前为止

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az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,方法的上边界Next是独占的,因此Next(15, 33)为您提供的值范围为15到32.

使用字符串的长度从中选择一个字符:

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,因此不应在函数内部创建随机数生成器.如果你将函数调用两次太近,你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)

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