Powershell将值转换为类型"System32 error

Question

我在Powershell中编写了一个脚本来收集有关我的归档文件夹中有多少文件的信息，该脚本将对文件夹中的文件进行计数，然后删除早于给定日期的文件，然后再次对文件数量进行计数，以报告它删除了多少文件。

我可以让它工作，但是我遇到了语法上的小问题。当我有这样的它时，它工作得很好。

Clear-Host

$ErrorFiles = "c:\data\ErrorFiles"
$Archivefiles = "c:\data\Archivefiles"

$PreCountErrorFiles = ((Get-ChildItem $ErrorFiles | Measure-Object).Count)
$PreCountArchivefiles = ((Get-ChildItem $Archivefiles | Measure-Object ).Count)

Get-ChildItem $ErrorFiles  | Where  {$_.LastWriteTime –lt ((Get-Date).AddDays(-10) )}  | ForEach { Remove-Item $_.FullName }
Get-ChildItem $Archivefiles | Where  {$_.LastWriteTime –lt ((Get-Date).AddDays(-10) )}  | ForEach { Remove-Item $_.FullName }

$PostCountErrorFiles = ((Get-ChildItem $ErrorFiles | Measure-Object).Count)
$PostCountArchivefiles  = ((Get-ChildItem $Archivefiles | Measure-Object ).Count)


$str1 = "Number of files in " + $ErrorFiles.ToString() + " was " + $PreCountErrorFiles.ToString() + " number of files deleted " + ($PreCountErrorFiles - $PostCountErrorFiles).ToString() + " and "  + $PostCountErrorFiles.ToString() + " are left." + "`n"  
$str2 = "Number of files in " + $Archivefiles.ToString() + " was " + $PreCountArchivefiles.ToString() + " number of files deleted " + ($PreCountArchivefiles - $PostCountArchivefiles).ToString() + " and "          + $PostCountArchivefiles.ToString() + " are left." + "`n"

write-host $str1
write-host $str2

但是，如果我尝试更改#str1赋值，使其在一行中，并获取两个字符串，我会得到这个错误(参见下面的代码)

无法将值"Number of files in“转换为"System.Int32”类型。错误：“输入字符串的格式不正确。”第13行: char:1 + $str1 = "Number of files in“+ $ErrorFiles.ToString() +”in“+ $PreCountErro ... ++ CategoryInfo : InvalidArgument：(:) []，RuntimeException + FullyQualifiedErrorId : InvalidCastFromStringToInteger

Clear-Host

$ErrorFiles = "c:\data\ErrorFiles"
$Archivefiles = "c:\data\Archivefiles"

$PreCountErrorFiles = ((Get-ChildItem $ErrorFiles | Measure-Object).Count)
$PreCountArchivefiles = ((Get-ChildItem $Archivefiles | Measure-Object ).Count)

Get-ChildItem $ErrorFiles  | Where  {$_.LastWriteTime –lt ((Get-Date).AddDays(-10) )}  | ForEach     { Remove-Item $_.FullName }
Get-ChildItem $Archivefiles | Where  {$_.LastWriteTime –lt ((Get-Date).AddDays(-10) )}  | ForEach     { Remove-Item $_.FullName }

$PostCountErrorFiles = ((Get-ChildItem $ErrorFiles | Measure-Object).Count)
$PostCountArchivefiles  = ((Get-ChildItem $Archivefiles | Measure-Object ).Count)


$str1 = "Number of files in " + $ErrorFiles.ToString() + " was " + $PreCountErrorFiles.ToString()     + " number of files deleted " + ($PreCountErrorFiles - $PostCountErrorFiles).ToString() + " and "  +     $PostCountErrorFiles.ToString() + " are left." + "`n"  +
- "Number of files in " + $Archivefiles.ToString() + " was " + $PreCountArchivefiles.ToString() + "     number of files deleted " + ($PreCountArchivefiles - $PostCountArchivefiles).ToString() + " and "  +     $PostCountArchivefiles.ToString() + " are left." + "`n"

write-host $str1

感谢您的帮助！

Answer 1

删除第二行开头的连字符：

$str1 = "Number of files in " + $ErrorFiles.ToString() + " was " + $PreCountErrorFiles.ToString()     + " number of files deleted " + ($PreCountErrorFiles - $PostCountErrorFiles).ToString() + " and "  +     $PostCountErrorFiles.ToString() + " are left." + "`n"  +
- "Number of files in " + $Archivefiles.ToString() + " was " + $PreCountArchivefiles.ToString() + "     number of files deleted " + ($PreCountArchivefiles - $PostCountArchivefiles).ToString() + " and "  +     $PostCountArchivefiles.ToString() + " are left." + "`n"
^

一般而言，格式运算符(-f)是构建如下字符串的更好方法：

$str1 = "Number of files in {0} was {1} number of files deleted {2} and {3} " +
        "are left.`nNumber of files in {4} was {5} number of files deleted " +
        "{6} and {7} are left.`n"
$str1 -f $ErrorFiles, $PreCountErrorFiles,
         ($PreCountErrorFiles - $PostCountErrorFiles),
         $PostCountErrorFiles, $Archivefiles, $PreCountArchivefiles,
         ($PreCountArchivefiles - $PostCountArchivefiles),
         $PostCountArchivefiles