如何在 Powershell 中添加最大循环？

Question

我想映射网络。如果映射失败，我需要使用重试，最大重试5次。我已经尝试过这种方式，但我无法弄清楚如何添加最大重试次数。

Do{
    Try{     
        $net = new-object -ComObject WScript.Network                   
        $net.MapNetworkDrive("$Directory", "\\IP\$Folder", $False, "$Server\$SQL", "$pass")
        $Message = "Mapping : " + $Directory + "Successful"
        Write-Host $Message
        
    }
    Catch{

         $Message= "Mapping : " + $Directory + " Fault" + " $_"
         Write-Host $Message
         # in here there is error handling.
         CallErrorHandlingFunction
    }
}While($? -ne $true)

# in here there is next process after network mapping  succesfull.
CallNextProcess

任何人都可以提供帮助，非常感谢。谢谢

Answer 1

有很多方法可以解决这个问题，这是一种使用script block的方法，请注意，此示例仅适用于您使用Write-Host，它的输出转到Information Stream，除非重定向，否则它的输出不会被捕获(6>&1)。

$action = {
    Try
    {
        $net = New-Object -ComObject WScript.Network                   
        $net.MapNetworkDrive(
            "$Directory", "\\IP\$Folder", $False, "$Server\$SQL", "$pass"
        )
        $Message = "Mapping : " + $Directory + "Successful"
        Write-Host $Message
        $true # => if everything goes right $result = $true
    }
    Catch
    {
        $Message = "Mapping : " + $Directory + " Fault" + " $_"
        Write-Host $Message
        $false # => if fails $result = $false
    }
}

$maxRetries = 5

do { $result = & $action }             # do this
until (-not --$maxRetries -or $result) # until $result is True OR
                                       # $maxRetries reaches 0

老实说，这是一个更简单的选择：

$maxRetries = 5

1..$maxRetries | ForEach-Object {
    if( & $action ) { break } # => if action = True stop the loop
}