I have converted an xls spreadsheet to xml by mapping the fields. When I go to import using the Import from file dialog I get the following error "Error importing: error, XML Data Import Not Supported". The version of Thingworx is ThingWorx 5.1.0.433.
Justin, how are you trying to import the XML file? The Import/ Export menu available at the top are for Entities/ Data and Extensions only. If you are looking to load data from an XML, you can use (or create a new service based on) some of the services like LoadXML available under Resources -> ContentLoaderFunctions. If you have a csv file, you can use the CSV Parser Extension available in the Marketplace.
I havent tried loading an xls file yet. You would have to have a extension written to load up each row to the DataTable. But, to make it go easier, if you can save the xls file as a csv, you can use the csv parser extension. That has a method to read the csv file. You can create a Datashape that matches the coloum of your csv file and use AddDataTableEntries service of the data table and small for loop to go through the rows to add.
