xml - 使用powershell通过xml节点的嵌套循环

Question

我想从一个XML文件中提取所有窗口节点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>

这是我编写的代码:

[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

我的期望:

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

我得到了:

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

怎么了结果与我对嵌套循环的工作原理的理解完全矛盾。

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的XPath，需要在.之前放置/。

因此，您的代码应为:

[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