问在使用Where-Object之后使用Get-随机创建一个空值表达式。

EN

Function Get-TempPassword {

    $TempPassword = $null

    $ascii = @()
    For ($a = 33;$a –le 126; $a++) { $ascii += ([char][byte]$a | Where-Object { $_ -notin "'",'`','|','_',";",'"',',' }) }

    Do {$TempPassword += $ascii | Get-Random; $loop++}

    Until ($loop -eq 11)

    return $TempPassword
}

$possible=36..38 + 40..43 + 45..58 + 60..94 + 97..123 + 125..126 + 33
(get-random -count 10 -input $possible | % {[char]$_}) -join ''

function New-SWRandomPassword {
    [CmdletBinding(DefaultParameterSetName='FixedLength',ConfirmImpact='None')]
    [OutputType([String])]
    Param
    (
        # Specifies minimum password length
        [Parameter(Mandatory=$false,
                   ParameterSetName='RandomLength')]
        [ValidateScript({$_ -gt 0})]
        [Alias('Min')] 
        [int]$MinPasswordLength = 8,

        # Specifies maximum password length
        [Parameter(Mandatory=$false,
                   ParameterSetName='RandomLength')]
        [ValidateScript({
                if($_ -ge $MinPasswordLength){$true}
                else{Throw 'Max value cannot be lesser than min value.'}})]
        [Alias('Max')]
        [int]$MaxPasswordLength = 11,

        # Specifies a fixed password length
        [Parameter(Mandatory=$false,
                   ParameterSetName='FixedLength')]
        [ValidateRange(1,2147483647)]
        [int]$PasswordLength = 10,

        # Specifies an array of strings containing charactergroups from which the password will be generated.
        # At least one char from each group (string) will be used.
        [String[]]$InputStrings = @('abcdefghijkmnpqrstuvwxyz', 'ABCEFGHJKLMNPQRSTUVWXYZ', '23456789', '!"#%&'),

        # Specifies a string containing a character group from which the first character in the password will be generated.
        # Useful for systems which requires first char in password to be alphabetic.
        [String] $FirstChar,

        # Specifies number of passwords to generate.
        [ValidateRange(1,2147483647)]
        [int]$Count = 1
    )
    Begin {
        Function Get-Seed{
            # Generate a seed for randomization
            $RandomBytes = New-Object -TypeName 'System.Byte[]' 4
            $Random = New-Object -TypeName 'System.Security.Cryptography.RNGCryptoServiceProvider'
            $Random.GetBytes($RandomBytes)
            [BitConverter]::ToUInt32($RandomBytes, 0)
        }
    }
    Process {
        For($iteration = 1;$iteration -le $Count; $iteration++){
            $Password = @{}
            # Create char arrays containing groups of possible chars
            [char[][]]$CharGroups = $InputStrings

            # Create char array containing all chars
            $AllChars = $CharGroups | ForEach-Object {[Char[]]$_}

            # Set password length
            if($PSCmdlet.ParameterSetName -eq 'RandomLength')
            {
                if($MinPasswordLength -eq $MaxPasswordLength) {
                    # If password length is set, use set length
                    $PasswordLength = $MinPasswordLength
                }
                else {
                    # Otherwise randomize password length
                    $PasswordLength = ((Get-Seed) % ($MaxPasswordLength + 1 - $MinPasswordLength)) + $MinPasswordLength
                }
            }

            # If FirstChar is defined, randomize first char in password from that string.
            if($PSBoundParameters.ContainsKey('FirstChar')){
                $Password.Add(0,$FirstChar[((Get-Seed) % $FirstChar.Length)])
            }
            # Randomize one char from each group
            Foreach($Group in $CharGroups) {
                if($Password.Count -lt $PasswordLength) {
                    $Index = Get-Seed
                    While ($Password.ContainsKey($Index)){
                        $Index = Get-Seed                        
                    }
                    $Password.Add($Index,$Group[((Get-Seed) % $Group.Count)])
                }
            }

            # Fill out with chars from $AllChars
            for($i=$Password.Count;$i -lt $PasswordLength;$i++) {
                $Index = Get-Seed
                While ($Password.ContainsKey($Index)){
                    $Index = Get-Seed                        
                }
                $Password.Add($Index,$AllChars[((Get-Seed) % $AllChars.Count)])
            }
            Return $(-join ($Password.GetEnumerator() | Sort-Object -Property Name | Select-Object -ExpandProperty Value))
        }
    }
}

New-SWRandomPassword