606689 - Error when calling listbox.getIndexOfItem

Status: VERIFIED INVALID

(Core :: XUL, defect)

Description

[Alexey Romanov]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.11) Gecko/20101012 Firefox/3.6.11 ( .NET CLR 3.5.30729; .NET4.0E) XPCOMViewer/0.9.2
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.11) Gecko/20101012 Firefox/3.6.11 ( .NET CLR 3.5.30729; .NET4.0E) XPCOMViewer/0.9.2

Calling listbox.getIndexOfItem on any XUL listbox gives an error.

Reproducible: Always

Steps to Reproduce:
call [code]getIndexOfItem[/code] on any XUL listbox. Here is an example which can be run in XUL Editor:
[code]<?xml-stylesheet href="chrome://global/skin/" type="text/css"?>
<window id="yourwindow" xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul" xmlns:html="http://www.w3.org/1999/xhtml" xmlns:h="http://www.w3.org/1999/xhtml">
 <listbox id="theList">
   <listitem label="Ruby"/>
 </listbox>

<script type="text/javascript">
<![CDATA[
var listbox = document.getElementById("theList");
listbox.appendItem(listbox.getIndexOfItem("Ruby"));
]]>
</script>
</window>[/code]
Actual Results:  
Received this error message in Error Console

Error: Could not convert JavaScript argument arg 0 [nsIListBoxObject.getIndexOfItem] = NS_ERROR_XPC_BAD_CONVERT_JS
Source file: chrome://global/content/bindings/listbox.xml
Line: 769

The listbox in preview window has one element:
Ruby

Expected Results:  
No error message, two elements in listbox:
Ruby
0

Comment 1

[Alexey Romanov]

Ok, sorry for stupidity. Apparently listbox.getIndexOfItem("Ruby") isn't looking for the element with the _label_ "Ruby", but the actual XUL list item object "Ruby", which obviously doesn't exist.

Comment 2

[Dave Garrett]

Verified invalid.

https://developer.mozilla.org/en/XUL/listbox#m-getIndexOfItem

Yep. The getIndexOfItem method takes a reference to a listitem as a parameter and returns its index. The getItemAtIndex method does the opposite and takes an index and returns a reference to the listitem at that index.

You need to pass getIndexOfItem a reference to the element itself, which you could get from document.getElementById if you give it an ID or by using document.querySelector or some other method.

By the way, this is not a forum so BBcode such as "[code]" will not work. For posting code testcases here, we generally recommend you attach the actual file(s) so they can be downloaded and run easily.