Hi Todd,
Thanks for using Syncfusion products.
When a column is hidden we can get the hidden column values , by accessing the particular cell value from the cell collections.
document.getElementById('TextBox1').innerText = gridObj.Row.tableRow.cells[2].innerText;
Here cells[2] denotes the hidden column cell.
Please have a look at the attached sample which illustrates this.
Regards,
Raji
HiddenCol_c40d5272.zip