InfoPath Dev

Most people must have read this article about concatenating values from a column of a repeat table. If you see the attached picture, I am dealing a different kind scenario-I am dealing with values collected from a multiple-selection list, what didn't work were "concat(Person, ";")" nor "eval(People, 'concat(my:Person, ";")')" nor "eval(eval(People, 'concat(my:Person, ";")'), "..")"

 How should I get the values collected by the multiple-selection list into a string that I could put in textbox?

Thanks 

Wei

Ok, after reading this page. I added a managed rule on to the Person field with an action to set the value to the field bound to the textbox with formula "eval(eval(Person, 'concat(., ",")'), "..")"

It only sort of worked as there are still two remaining issues:

1) leading "," in the textbox

2) when I unchecked item in the multiple selection list, the textbox is not updated....

Shouldn't unchecking an item in the Multiple-Selection List also trigger the action to update value of the textbox?

 The InfoPath Form's XML content is like following, and kind of explained the reason behind the leading ",", but why should this happen?:

<?xml version="1.0" encoding="utf-8"?>
<?mso-infoPathSolution name="urn:schemas-microsoft-com:office:infopath:ConcatTest:-myXSD-2012-04-02T21-21-26" solutionVersion="1.0.0.2" productVersion="14.0.0.0" PIVersion="1.0.0.0" href="http://bgqw5j1/FormServerTemplates/ConcatTest.xsn"?>
<?mso-application progid="InfoPath.Document" versionProgid="InfoPath.Document.3"?>
<my:myFields xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:my="http://schemas.microsoft.com/office/infopath/2003/myXSD/2012-04-02T21:21:26" xmlns:xd="http://schemas.microsoft.com/office/infopath/2003" xml:lang="en-US">
    <my:People>
        <my:Person></my:Person><my:Person>John</my:Person><my:Person>James</my:Person><my:Person>Joe</my:Person><my:Person>Daniel</my:Person>
    </my:People>
    <my:ConcatNames>,John,James,Joe,Daniel,</my:ConcatNames>
</my:myFields>

Found Jimmy's answers to this post: http://www.infopathdev.com/forums/p/14658/52125.aspx

Very much what I wanted to do, what I still don't get is that why we need to set the default value of the textbox field/control, wasn't it bound to the field already and we are assigning a new value to that field whenever we change the multiple selection list?

Could one of the steps(assigning value action, and default value of the field) be redundant?  Thx

Thank you! You helped me a lot!