We always try to keep the size of the iGrid OCX as small as possible (and not to bloat the control with many features), and that's why iGrid does not have a built-in method to upload data from files of different formats.
However, we provide our users with many source code samples for such typical tasks, and that's true for this case as well.
The first sample from the iGrid main demo, My Customers, loads the data from a comma-separated values file. The data are stored in the file CustList.txt - you can look inside it. MyCust.frm contains the source code you can take and use in your apps to read/write CSV files.