I can help with some of your problems:

>4) Actually, Ordering and Search are most difficult.
> How to check the selected Field has been set the Tag() ?!
> If so, set the order when interactivechange of field

I make the headers of each grid column clickable to set the order for searching. By default, my grid class sets orderable columns to blue foreground and the currently ordered column forecolor in red. I have 3 properties of the grid: 1 for tablename to search, the order tag to use and the fieldname to search. I have a custom method of the grid that is called by the click events of the column headers. I pass to the method which column number was clicked. I then set the column header forecolors, change the table order, etc. You will have to have additional logic to handle switching of tables as well.

I then can use an incremental search textbox that also has custom properties of the table, index tag, etc., to use in the search. Since I have a fieldname property, when my incremental search textbox is used I can test the field type using the type() function.

>5) use don't want to add '' for text and {} for date on search
> How to check the type of field to set the Locate statement.
> because type() got error.
>

>7) Finally, I wonder I cannot use 'Like' on Locate Command!!
>Because I can:
>Select * from myTable where key Like '%FC0_2%' into cursor tmp
>to set the grid with special search
>but normal locate will got error.
>So, how to change [locate for key like '%FC0_2%']
>into a valid locate command? Of cos, The difficulty is to put on
>the orginal statement without affect others. )_('
>
>
LIKE is strictly for SQL statements. You can issue:

Locate for "someval" $somefield

which will return records with *someval* anywhere in *somefield*