Hi all,

I've written an Excel add-in that allows users to input a list of
formulas that they want "frozen" (i.e. - converted to the formula's
value). For example:

Listbox control on userform contains the following values:
HPVAL
HPEA

userform has Add and Remove buttons to modify this list. userform also
has buttons to freeze the results of these formulas on the current
sheet or throughout the entire workbook.

When the user clicks to freeze button, a routine in the addin looks
through all cells to determine if the formulas in the list are
contained in the cell's formula. If so, the formula is replaced with
its value.

I currently determine if the formula exists in the cell by looking for
the string "=HPVAL(" in the case of the first formula listed above.
So, if the user has typed in "+HPVAL(", the formula is not forzen. Or,
if for some reason the user has a formula something like this:
=IF(A1="My string: =HPVAL(",1,0), then that formula would be frozen,
even though clearly HPVAL used in this context is not a formula, but a
constant string. Another issue is, if the user has the following
formula: =IF(HPVAL(<<stuff here)=1,1,0), then the ENTIRE formula is
converted to its value, and not just the HPVAL part.

All of these problems stem from the fact that I'm looking for "strings"
that represent the formula instead of looking for the formula itself.
Is there a way to examine a cell, determine if a given formula is
utilized in the cell, and freeze its value? Has anyone out there
written an add-in or VBA routine that does the same thing? Your
thoughts are greatly appreciated.

Thanks,
Johnny