How to check whether a node exists or not using powershell without getting exception?

Question

I am trying to check whether a particular node exists or not like follows.

In my config file there is a node named client ,it may or may not available.

If it is not available i have to add it.

    $xmldata = [xml](Get-Content $webConfig)    

        $xpath="//configuration/system.serviceModel"    
        $FullSearchStr= Select-XML -XML $xmldata -XPath $xpath

If ( $FullSearchStr -ne $null) {  

        #Add client node
        $client = $xmldata.CreateElement('Client')
        $client.set_InnerXML("$ClientNode")
        $xmldata.configuration."system.serviceModel".AppendChild($client) 
        $xmldata.Save($webConfig) 

    }

The condition i am checking may return array.

i would like to check whether the client node available before or not?

score 10 · Answer 1 · answered Oct 23 '12 at 13:33

10

You can try the SelectSingleNode method:

$client = $xmldata.SelectSingleNode('//configuration/system.serviceModel/Client')

if(-not $client)
{
    $client = $xmldata.CreateElement('Client')
    ...
}

answered Oct 23 '12 at 13:33

Shay Levy

121,444
32
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The condition succeeds even if 'client' node is there already – Samselvaprabu Oct 23 '12 at 13:45
If the xpath is passed as variable like this $xpath='//configuration/system.serviceModel/client' $client = $xmldata.SelectSingleNode($xpath) it fails , but if i pass the xpath directly then it works fine. Peculiar logic!!! what am i missing MVP? – Samselvaprabu Oct 23 '12 at 16:20

score 4 · Accepted Answer · answered Oct 24 '12 at 06:05

4

Why can't you just do something like:

$xmldata = [xml](Get-Content $webConfig)    
$FullSearchStr = $xmldata.configuration.'system.serviceModel'

answered Oct 24 '12 at 06:05

Andrey Marchuk

13,301
2
36
52

score 3 · Answer 3 · answered Sep 23 '16 at 05:48

3

You can also use 'count' like a boolean

if ($xmldata.SelectSingleNode('//configuration/system.serviceModel/Client').Count)
{
 The count is 1 or more, so it exists
}
else
{
 The count is 0, so it doesn't exists
}

answered Sep 23 '16 at 05:48

Jason Hershey

31
2

That has to be wrapped to get the count. `if (@($xmldata.SelectSingleNode('//configuration/system.serviceModel/Client')).Count -gt 0)` – StingyJack Oct 18 '17 at 13:14

How to check whether a node exists or not using powershell without getting exception?

3 Answers3

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