I am also trying to make a Undo function.
But, the Undo functionality will depend on where you are using it.
e.g. If you are using Undo on records or textbox.
If you are using it on a database then simply stores the data, steps
into some other file. e.g. if you have deleted some records and then
you want to Undo it. In this case stores the deleted records, steps
in some other file or simply give Recall command after keeping a
check which records you want to Recall.
Also, go on storing nos. for the steps you are doing because while
doing Undo you have to do the same steps but in Reverse direction.
As far as textbox in concernced I am also trying Undo.

Any ideas about Undo function for Text Box.