I tried an example containing a charindex column in SQL2005, and while it did create the index on the view, the following warning was shown when it was created.

Warning: The optimizer cannot use the index because the select list of the view contains a non-aggregate expression.

The execution plan for queries using the view show the use of indexes on the underlying tables, rather than the index on the view.

So, while the system allows you to create an index on a view containing a charindex column, it doesn't appear to be of any use.