使用powershell通过xml节点嵌套循环

Question

我想从 xml 文件中提取所有窗口和所有视点节点的名称属性值。

<?xml version='1.0' encoding='utf-8' ?>
        <workbook>
            <windows>
                <window class='dashboard' name='D1'>
                  <viewpoints>
                    <viewpoint name='V1'> </viewpoint>
                    <viewpoint name='V2'> </viewpoint>
                    <viewpoint name='V3'> </viewpoint>
                </viewpoints>
                </window>
                <window class='dashboard' name='D2'>
                  <viewpoints>
                    <viewpoint name='V10'> </viewpoint>
                    <viewpoint name='V11'> </viewpoint>
                  </viewpoints>
                 </window>
            </windows>
        </workbook>

这是我写的代码：

[XML]$doc = get-content -path 'W:\Demo1.xml'


$objs = @()
$dashboards = $doc.SelectNodes("//window[@class = 'dashboard']")

foreach ($dashboard in $dashboards)
{
   $worksheets = $dashboard.SelectNodes("//viewpoint[@name]")

    foreach ($worksheet in $worksheets)
    {
        $obj = new-object psobject -prop @{Dashboard=$dashboard.name; Worksheet = $worksheet.name}; 
        $objs += $obj;

    }  
 } 

$objs

---

我的预期：

仪表板 工作表 D1 V1 D1 V2 D1 V3 D2 V10 D2 V11

我得到了什么：

仪表板 工作表 D1 V1 D1 V2 D1 V3 D1 V10 D1 V11 D1 V14 D2 V1 D2 V2 D2 V3 D2 V10 D2 V11 D2 V14

这里有什么问题？结果与我对嵌套循环如何工作的理解完全矛盾。

Answer 1

以/ 字符开头的XPath 意味着它将从文档根节点开始。要从上下文节点创建相对 XPath，您需要在 / 之前放置一个 .。

所以你的代码应该是：

[XML]$doc = get-content -path 'W:\Demo1.xml'


$objs = @()
$dashboards = $doc.SelectNodes("//window[@class = 'dashboard']")

foreach ($dashboard in $dashboards)
{
   $worksheets = $dashboard.SelectNodes(".//viewpoint[@name]")

    foreach ($worksheet in $worksheets)
    {
        $obj = new-object psobject -prop @{Dashboard=$dashboard.name; Worksheet = $worksheet.name}; 
        $objs += $obj;

    }  
 } 

$objs

Answer 2

您还可以简化它并采用您的 xpath 从仪表板窗口中选择所有 viewpoint 节点：

[XML]$doc = get-content -path 'W:\Demo1.xml'

$objs = @()
$worksheets = $doc.SelectNodes("//window[@class = 'dashboard']//viewpoint[@name]")

foreach ($worksheet in $worksheets)
{
    $obj = new-object psobject -prop @{Dashboard=$worksheet.ParentNode.ParentNode.name; Worksheet = $worksheet.name}; 
    $objs += $obj;
}  

$objs

这里是没有xpath的解决方案：

[XML]$doc = get-content -path 'W:\Demo1.xml'

$objs = $doc.DocumentElement.windows.window | Where class -eq 'dashboard' | foreach {
    $dashboardName = $_.name
    $_.viewpoints.viewpoint | foreach {
        new-object psobject -prop @{Dashboard=$dashboardName; Worksheet = $_.name}
    }
}