DataGridItem Headers and index out of range error

Question

Hi all, wondering if anyone can help me with an annoying little problem I'm encountering. I have a datagrid storing characters along with their statistics, if the user selects a character I have a button appearing to link to that character. However I now have the problem that if the user selects a header to sort the datagrid the button to display character information appears and clicking it results in an index out of range error. I've tried a simple if " " with no luck and various other quick fix theories all with no such luck. Thanks in advance!