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Pull selectedIndex from API
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MattGrover  
#1 Posted : Tuesday, March 21, 2023 9:58:38 PM(UTC)
MattGrover

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Hi All,

I'm working on a new bit of script in which I'm pulling from the API XML for the first time, I'm getting the error Error Line 9: Object reference not set to an instance of an object.

My guess at the moment is I'm not understanding the syntax for pulling info out of a XML path/line/appropriate term.
At this stage I'm trying to pull the current selectedIndex of a List Input to then use in the rest of the script. Any guidance as to what I'm doing wrong is much appreciated.
Thanks!

Code:
'Grab Selected Index Test

'load vMix API xml in to memory
dim xml as string = API.XML()
dim x as new system.xml.xmldocument
x.loadxml(xml)

'check slide number and display
    dim CurrentSlide as String = (x.SelectSingleNode("//input[@title='holding']//selectedIndex").InnerText)
    console.writeline(CurrentSlide)
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doggy  
#2 Posted : Tuesday, March 21, 2023 11:20:55 PM(UTC)
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The xpath is not refering to an existing node
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dmwkr  
#3 Posted : Tuesday, March 21, 2023 11:29:47 PM(UTC)
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Look for the difference between Elements and Attributes:
https://www.w3schools.com/xml/xml_attributes.asp

And look how their contents are referenced as "InnerText" and "Value":
https://forums.vmix.com/...86-Scripting-for-Dummies
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doggy  
#4 Posted : Tuesday, March 21, 2023 11:33:25 PM(UTC)
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try (x.SelectSingleNode("//input[@title='holding']/@selectedIndex").Value)

But do what DMWKR said for future reference
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MattGrover  
#5 Posted : Wednesday, March 22, 2023 1:03:08 AM(UTC)
MattGrover

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Quote:

The xpath is not refering to an existing node


Yes, I'm presuming my xpath is incorrect..

Quote:
try (x.SelectSingleNode("//input[@title='holding']/@selectedIndex").Value)

But do what DMWKR said for future reference


This gave the same error. Error Line 9: Object reference not set to an instance of an object.

I looked at the links DMWKR posted (thanks) and I'm already using the Scripting for Dummies examples (and others) as a reference, but what I don't understand at the moment it seems is the structure of the xpath in this instance.

the xml line I'm working with is

Code:
<input key="e285d586-c76c-493f-90ed-1c34d2f6ce83" number="23" type="VideoList" title="holding - Socials.png" shortTitle="holding" state="Running" position="0" duration="0" loop="False" muted="True" volume="100" balance="0" solo="False" audiobusses="" meterF1="0" meterF2="0" gainDb="0" selectedIndex="1">
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dmwkr  
#6 Posted : Wednesday, March 22, 2023 1:19:19 AM(UTC)
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Originally Posted by: MattGrover Go to Quoted Post

Code:
<input key="e285d586-c76c-493f-90ed-1c34d2f6ce83" number="23" type="VideoList" title="holding - Socials.png" shortTitle="holding" state="Running" position="0" duration="0" loop="False" muted="True" volume="100" balance="0" solo="False" audiobusses="" meterF1="0" meterF2="0" gainDb="0" selectedIndex="1">


You are using "holding" as title. But the "title" is "holding - Socials.png", "shortTitle" would be "holding".
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MattGrover  
#7 Posted : Wednesday, March 22, 2023 1:27:58 AM(UTC)
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Goddammit I'm an idiot!

Thank you!

So looks like a combo of using the wrong title reference (hence why it didn't exist) and ALSO my formatting of "//selectedIndex" which didn't work, but changing it to "/@selectedIndex" as Doggy suggested makes the line work now. I'll do more research to understand the why

Thanks to both of you!
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