InfoPath Dev

 Greetings all, I have had the greatest headache overcoming this problem! I am new to C# and XML. I have an InfoPath 2013 form that gets it data from a SQL table through a data connection. I need to filter the data using wildcards. I have been following Microsoft's directions to accomplish this (http://support.microsoft.com/kb/826992). I made the custom changes to suit my needs and I have followed the code letter for letter. but when I run the code, it crashes right where I enter the text to use in the query. The error message I get is "NullReferenceException was unhandled by user code : Object reference not set to an instance of an object." I have been beating my head against the wall trying to figure this one out. I have searched extensively but nothing is helping. Here is the offending line:

string strPart_ID = xnSuppliersQuery.SelectSingleNode("@Part_ID", this.NamespaceManager).Value;

I can't see your screenshot - can you post more of your code? Maybe a screenshot of the schema in question? You can attach your screenshot under the Options tab in a reply.

 Here is the screenshot. Offending line is highlighted.

thanks!

wakgtech 

So, your form is bound to a SQL DB? If you go to the fields task pane, and right click the query field PART_DIMENSION and select copy XPath, what is the resulting XPath? I'm thinking your XPath Navigator xnSuppliersQuery is null. Do you know how to run your code in debug? If not, I have a blog post that may help you - http://www.infopathdev.com/blogs/hilary/archive/2009/09/27/debug-managed-code-in-vsta-for-the-accidental-programmer.aspx

 This is my resulting XPath "/dfs:myFields/dfs:queryFields/q:PART_DIMENSION" is this not correct? I will now look at your blog post! Thanks for your assistance!

xnMain.SelectSingleNode is not using that XPath tho, right? :)

Edited to add the line of code, I was being lazy -

XPathNavigator xnSuppliersQuery = xnMain.SelectSingleNode(""/dfs:myFields/dfs:queryFields/q:PART_DIMENSION", this.NamespaceManager);

 OK, I did find that I had to change my code for the var xnSuppliersQuery. But it still hangs at the same place.

Bill 

Hover your cursor over xnSuppliersQuery - is it null? If not, what is the full XPath to the field you are trying to set the value of?

when I hover over xnSuppliersQuery, it is NOT null. I am thinking the full xpath is

 I turned on a few watches and this is what I got. Any Ideas?

You just have a : before Part_ID - there would be something before that- just right click the query field and copy the XPath - paste it in a reply.

 /dfs:myFields/dfs:queryFields/q:PART_DIMENSION/@PART_ID

That was it!!!!!!!!!!!!! Problem solved. You are a Goddess! Thank You very much! This has been a stickler of a problem here and this will make me look very good! Thank you so much. If you have written any books, send me some links!

WAKGTECH
(another thankful customer) 

XPath is case sensitive - gotta watch those caps! Glad you solved it - you'll sleep well tonight.

Isn't it fun when you bend the computer to your will?