管道中的第一个对象（或Select-Object等）定义了输出的头，无论是文件还是控制台输出。
你可以做的是分两轮将它们转换为csv，并将其添加到同一个文件中。

$inputFile.Transaction.TXNHEAD | ConvertTo-Csv -NoTypeInformation -Delimiter ";" | Set-Content -Path "c:\pstest\test.csv" -Encoding UTF8
$inputFile.Transaction.TXNDETAIL | ConvertTo-Csv -NoTypeInformation -Delimiter ";" | Add-Content -Path "c:\pstest\test.csv" -Encoding UTF8

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您也可以像这样合并：

$inputFile.Transaction.TXNHEAD, $x.Transaction.TXNDETAIL |
ForEach-Object { $_ | ConvertTo-Csv -NoTypeInformation -Delimiter ";" } |
Set-Content -Path "c:\pstest\test.csv" -Encoding UTF8

型

下面是我的代码：

# ============================================================================= 
#  
# NAME:xml2csv.ps1
#  
# AUTHOR: 
# THANKS TO: Rick Sheeley (original snippet on STack Overflow) 
# DATE  : 
#  
# COMMENT:  
# Send large XML with multiple children and Attributes to CSv for analysis
#
# Note: For versions 3.0 or newer only
# ============================================================================= 

function Get-Attributes([Object]$pnode)
{

    if($pnode.HasAttributes) {

        foreach($attr in $pnode.Attributes) {

            $xattString+= $attr.Name + ":" + $attr."#text" + ","

        }

    }

    else {

            $xattString = $pnode.nNode + ": No Attributes,"

    }

    return $xattString
}

function Get-XmlNode([ xml ]$XmlDocument, [string]$NodePath, [string]$NamespaceURI = "", [string]$NodeSeparatorCharacter = '.')
{
    # If a Namespace URI was not given, use the Xml document's default namespace.
    if ([string]::IsNullOrEmpty($NamespaceURI)) { $NamespaceURI = $XmlDocument.DocumentElement.NamespaceURI }   

    # In order for SelectSingleNode() to actually work, we need to use the fully qualified node path along with an Xml Namespace Manager, so set them up.
    $xmlNsManager = New-Object System.Xml.XmlNamespaceManager($XmlDocument.NameTable)
    $xmlNsManager.AddNamespace("ns", $NamespaceURI)
    $fullyQualifiedNodePath = "/ns:$($NodePath.Replace($($NodeSeparatorCharacter), '/ns:'))"

    # Try and get the node, then return it. Returns $null if the node was not found.
    $node = $XmlDocument.SelectSingleNode($fullyQualifiedNodePath, $xmlNsManager)
    return $node
}

cls
$fin = "<Filepath>\<myFile>.xml"
$fout = "<Filepath>\<myFile>.csv"

Remove-Item $fout -ErrorAction SilentlyContinue

[xml]$xmlContent = get-content $fin
$row=0
$COMMA=","
$pNode = "ROOT"

# Replace all "MyTopNode" with your top node...

$nNode = "MyTopNode"

$xmlArray  = @(
    [pscustomobject]@{Row= $row;Parent=$pNode;Node=$nNode;Attribute='';ItemType='Root';Value=''})

$xmlArray[$row].Row = $row
$xmlArray[$row].Parent = $pNode
$xmlArray[$row].Node = $nNode
$xmlArray[$row].Attribute = ""
$xmlArray[$row].ItemType = "Root"
$xmlArray[$row].Value = $attr."#text"
$row++

if($xmlContent.MyTopNode.HasAttributes) {

    foreach($attr in $xmlContent.MyTopNode.Attributes) {

        $xmlArray += @(
            [pscustomobject]@{Row= $row;Parent=$pNode;Node=$nNode;Attribute='';ItemType='Root';Value=''})

        $xmlArray[$row].Row = $row
        $xmlArray[$row].Parent = $pNode
        $xmlArray[$row].Node = $nNode
        $xmlArray[$row].Attribute = $attr.LocalName
        $xmlArray[$row].ItemType = "Attribute"
        $xmlArray[$row].Value = $attr."#text"
        $row++

    }

}

# Begin TRY

try {

    foreach($node in $xmlContent.MyTopNode.ChildNodes) {

        $pNode = "MyTopNode"

        $nNode = $node.LocalName

        $xmlArray += @(
            [pscustomobject]@{Row= $row;Parent=$pNode;Node=$nNode;Attribute='';ItemType='Root';Value=''})

        $xmlArray[$row].Row = $row
        $xmlArray[$row].Parent = $pNode
        $xmlArray[$row].Node = $nNode
        $xmlArray[$row].Attribute = ""
        $xmlArray[$row].ItemType = "Root"
        $xmlArray[$row].Value = $attr."#text"
        $row++

        if($nNode.HasAttributes) {

            foreach($attr in $node.Attributes) {

                $xmlArray += @(
                    [pscustomobject]@{Row= $row;Parent=$pNode;Node=$nNode;Attribute='';ItemType='Root';Value=''})

                $xmlArray[$row].Row = $row
                $xmlArray[$row].Parent = $pNode
                $xmlArray[$row].Node = $nNode
                $xmlArray[$row].Attribute = $attr.LocalName
                $xmlArray[$row].ItemType = "Attribute"
                $xmlArray[$row].Value = $attr."#text"
                $row++

            }

        }

        foreach($sNode in $node.ChildNodes) {

            $pNode = $nNode
            $snNode = $sNode.LocalName

            $xmlArray += @(
                [pscustomobject]@{Row= $row;Parent=$pNode;Node=$nNode;Attribute='';ItemType='Root';Value=''})

            $xmlArray[$row].Row = $row
            $xmlArray[$row].Parent = $pNode
            $xmlArray[$row].Node = $snNode
            $xmlArray[$row].Attribute = ""
            $xmlArray[$row].ItemType = "Root"
            $xmlArray[$row].Value = $attr."#text"
            $row++

            if($sNode.HasAttributes) {

                foreach($attr in $sNode.Attributes) {

                    $xmlArray += @(
                        [pscustomobject]@{Row= $row;Parent=$pNode;Node=$nNode;Attribute='';ItemType='Root';Value=''})

                    $xmlArray[$row].Row = $row
                    $xmlArray[$row].Parent = $pNode
                    $xmlArray[$row].Node = $snNode
                    $xmlArray[$row].Attribute = $attr.LocalName
                    $xmlArray[$row].ItemType = "Attribute"
                    $xmlArray[$row].Value = $attr."#text"
                    $row++

                }

            }
        }
    }

    $xmlArray | SELECT Row,Parent,Node,Attribute,ItemType,Value | Export-CSV $fout -NoTypeInformation
}

# End TRY

# Begin Catch

Catch [System.Runtime.InteropServices.COMException]
{
    $ErrException = Format-ErrMsg -errmsg $_.Exception
    $ErrorMessage = $_.Exception.Message
    $ErrorID = $_.FullyQualifiedErrorId
    $line = $_.InvocationInfo.ScriptLineNumber

    Write-Host                           "  "
    Write-Host                           "  "
    Write-Host -ForegroundColor DarkMagenta  ""
    Write-Host -ForegroundColor Magenta      "==!!Error!!==!!Error!!==!!Error!!==!!Error!!==!!Error!!==!!Error!!==!!Error!!==!!Error!!==!!Error!!==!!Error!!==!!Error!!==!!Error!!==!!Error!!=="
    Write-Host -ForegroundColor DarkMagenta  ""
    Write-Host -ForegroundColor DarkCyan     "Details:"  
    Write-Host -ForegroundColor White        "---------------------------------------------------------------------------------------------------------------------------------------------------- "
    Write-Host -ForegroundColor Cyan         "`t  Module:        $modname"
    Write-Host -ForegroundColor Cyan         "`t Section:        $sFunc"
    Write-Host -ForegroundColor Cyan         "`t On Line:        $line"
    Write-Host -ForegroundColor Cyan         "`t File:           $fSearchFile | Search will be skipped!!"
    Write-Host -ForegroundColor White        "---------------------------------------------------------------------------------------------------------------------------------------------------- "
    Write-Host -ForegroundColor DarkCyan      "Exception Message:"  
    Write-Host -ForegroundColor White       "---------------------------------------------------------------------------------------------------------------------------------------------------- "
    Write-Host -ForegroundColor Yellow       "`t ShortMessage:   $ErrorMessage"       
    Write-Host -ForegroundColor Yellow       "`t ErrorID:        $ErrorID"
    Write-Host -ForegroundColor White        "---------------------------------------------------------------------------------------------------------------------------------------------------- "
    Write-Host -ForegroundColor Magenta      "$ErrException"  
    Write-Host -ForegroundColor White        "---------------------------------------------------------------------------------------------------------------------------------------------------- "
    Write-Host -ForegroundColor DarkMagenta  "========================================================================================================================================== "
    Write-Host -ForegroundColor Yellow       "This File will be added to the Skip list. Please restart script $sScriptName ...." 
    Write-Host -ForegroundColor DarkMagenta  "========================================================================================================================================== "
    Write-Host                           "  "
    Write-Host                           "  "
}

Catch
{
    $ErrException = Format-ErrMsg -errmsg $_.Exception
    $ErrorMessage = $_.Exception.Message
    $ErrorID = $_.FullyQualifiedErrorId
    $line = $_.InvocationInfo.ScriptLineNumber

    Write-Host                           "  "
    Write-Host                           "  "
    Write-Host -ForegroundColor DarkRed  "================================================================================================================================================="
    Write-Host -ForegroundColor Red      "==!!Error!!==!!Error!!==!!Error!!==!!Error!!==!!Error!!==!!Error!!==!!Error!!==!!Error!!==!!Error!!==!!Error!!==!!Error!!==!!Error!!==!!Error!!=="
    Write-Host -ForegroundColor DarkRed  "================================================================================================================================================="
    Write-Host -ForegroundColor DarkCyan "Details:"  
    Write-Host -ForegroundColor White    "---------------------------------------------------------------------------------------------------------------------------------------------------- "
    Write-Host -ForegroundColor Cyan     "`t  Module:        $modname"
    Write-Host -ForegroundColor Cyan     "`t Section:        $sFunc"
    Write-Host -ForegroundColor Cyan     "`t On Line:        $line"
    Write-Host -ForegroundColor Cyan     "`t File:           $fSearchFile"
    Write-Host -ForegroundColor White    "---------------------------------------------------------------------------------------------------------------------------------------------------- "
    Write-Host -ForegroundColor DarkCyan "Exception Message:"  
    Write-Host -ForegroundColor White    "---------------------------------------------------------------------------------------------------------------------------------------------------- "
    Write-Host -ForegroundColor Yellow      "`t ShortMessage:   $ErrorMessage"       
    Write-Host -ForegroundColor Magenta  "`t ErrorID:        $ErrorID"
    Write-Host -ForegroundColor White    "---------------------------------------------------------------------------------------------------------------------------------------------------- "
    Write-Host -ForegroundColor Red      "$ErrException"  
    Write-Host -ForegroundColor White    "---------------------------------------------------------------------------------------------------------------------------------------------------- "

# Show etended error info if in debug mode.

    if ($extDebug -eq $true) {

        Write-Host -ForegroundColor White    "---------------------------------------------------------------------------------------------------------------------------------------------------- "
        Write-Host -ForegroundColor Red      "Extended Debugging info"  

        Write-Host -ForegroundColor White    "---------------------------------------------------------------------------------------------------------------------------------------------------- "
        $error[0].Exception | Format-List * -Force
        Write-Host -ForegroundColor White    "---------------------------------------------------------------------------------------------------------------------------------------------------- "

    }

    Write-Host -ForegroundColor DarkRed  "==================================================================================================================================================== "
    Write-Host -ForegroundColor DarkRed  "==================================================================================================================================================== "
    Write-Host                           "  "
    Write-Host                           "  "

    Break

# End Catch

}

# Begin Finally

Finally
{
    "finis."
    Exit 0

# End Finally

}

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