I have an MDI frame with child windows A and B. Window A browses cursor 1 showing records from table A. Window B browses cursor 2 showing records from table B.

From window A, I wish to use the active cursor temporarily in some other process, say a viewer popup. So I make a temporary copy of the cursor with the following code:

TempCursor=0

ClearSelect TempCursor

Select.Seek( Seek$Top, Cursor, 0, Flag )

Swap.Cursor( Cursor, TempCursor, Swap$Copy )

... (temporary process follows)

Where, Cursor=1, Seek$Top=0, and Swap$Copy=2. When the temporary process finishes, I continue to browse cursor 1 in window A without problems.

Next I change focus to window B, where cursor 2 is active, and the correct list is being browsed. Again, I call my temporary process code, where this time cursor=2.

After which, I discover that Window B is browsing keys from cursor 1, table A. Woah, Nelly! What happened here?

(Questions or comments about the Select.Seek and SwapCursor routines are welcome.)

Gerald

glovel@wares.cc

Did some more testing on this. Started windows A and B. Performed a select into cursor 0 in window A, and used SWAP.CURSOR to copy the results into cursor 1. Switched to window B. Cleared cursor 0, performed a select into cursor 0, and used SWAP.CURSOR to copy the results into cursor 2.

I can tell you that window A, browsing cursor 1, loses its list when any other process clears or uses cursor 0. Therefore SWAP.CURSOR is moving the pointers around in @CURSORS, but the internals where the key list resides is still associated with cursor 0. If SWAP.CURSOR could really move a cursor pointer and its list from 0 to another cursor, it would be very nice.

Many commands work with cursor 0 only. This is actually a good thing, because cursor 0 always terminates when BASIC exits. So if you need a temporary cursor for a command or a BASIC routine, you can be assured that cursor 0 is available (until BASIC becomes multithreaded?). But once a select or list operation which is limited to cursor 0 returns a cursor, there needs to be a way to pass that cursor on to a persistent process such as a window. Making a cursor persistent means transferring ALL its information into the new cursor, not just SOME of the pointers.

Of course, I can use my CURSOR2LIST routine to make a key list from from the cursor (ugh). Somehow my enthusiasm for this solution is limited. Any reason why SWAP.CURSOR can't be made to work?

Gerald

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