.Bookmark property invalid

[MatthewGrace]

I have encountered an odd situation where the bookmark property doesn't seem to want to behave.



It is important that my user be able to .Requery her subdatasheet and not end up losing her place. No problem:

    Dim strBookmark As String
    strBookmark = Me.subOrders.Form.Bookmark
    Me.subOrders.Form.Requery 
    Me.subOrders.Form.Bookmark = strBookmark

and it works - most of the time. Oddly, if you put on a filter of any kind in the Subdatasheet and ran just these 4 lines on a button_click event, you'll get an Invalid Bookmark error. Close the error dialog and try again - everything works just fine. Now toggle the filter off and you'll get the Invalid Bookmark error dialog again. Close it and everything works fine.

Seems like the first Requery after you apply a filter invalidates a previously stored bookmark... at least in this DB, I cannot reproduce it elsewhere.

Have a look if you want. The only button/code you need concern yourself with is the one captioned "Command117", and the Datasheet subform right above it. The "order manager" Form where all this is happening should open automatically.

I've got a workaround, but I feel like I need closure as to why this is happening.

[RuralGuy]

See if this does what you want and then we can talk. BTW, did you know that a Bookmark is not a String?

[MatthewGrace]

Thank you RuralGuy, this is the same workaround I finally settled on, only yours is better written.

You mentioned that .Bookmark is not a string, and I have been wondering about this for a while:
The help file for Recordset.Bookmark(https://msdn.microsoft.com/en-us/lib.../ff823084.aspx ) says "To create a bookmark for a record other than the current record, move to the desired record and assign the value of the Bookmark property to a String variable that identifies the record. (bold letters theirs)" But the help file for the Form.Bookmark identifies itself as a "Read/Write Variant".

#1) What's the Difference Between Form.Bookmark and Form.Recordset.Bookmark?

#2) Along the same vein in this example, what's the difference between Me.Subformname.Requery, Me.Subformname.Form.Requery, and Me.Subformname.Form.Recordset.Requery?

#3) I'll digress and say I hate the "Variant" datatype . Even after reading the MSDN file on them, which tells you "what it is" - how/why I would wisely use it in practice, I don't understand. Why not just disambiguate your variables and write, Long, String, Recordset, etc. When would a programmer NOT know his variables intended use in advance? If you know a good primer on this, I'm all ears.

Thank you for any insight.

[RuralGuy]

You are correct about the ambiguity of that msdn link. I've always used a Variant datatype but Access is good at coercing a variable to what you need. As for all of the different versions of the syntax that is Access in the background helping again. I would stick with the Me.Subformname.Form.Recordset.Requery syntax incase ms decides to deprecate the other versions. I would say that any time you requery a recordset the bookmark can become invalid which is why I chose the [ID] which will not change unless you filter that record out. 8^) Have a good one.