Hello, Tracy

In the meantime, I solved the problem. Look what I did:

I populate the treeview from a table. It contains 3 columns: ID, ParentId and SortOrder. All of them Integers. Treeview nodes are filled up in a recursive method. I can post that code, if necessary.

A small example of the table:

iId         iParentId         iSortOrder
1           0                 1
2           1                 1
3           1                 2
4           1                 3
5           2                 1
6           2                 2
7           2                 3
8           0                 2

The values from iSortOrder column are written when a node is added first time.


The code for moving a node up (under the same parent) follows:

<pre>
IF VARTYPE(THISFORM.Tree.SELECTEDITEM) = "O"
*!* User did select a node, but I'll do some checking first
	liCurrentKey = THISFORM.Tree.SELECTEDITEM.KEY

	IF VARTYPE(THISFORM.Tree.SELECTEDITEM.PARENT) # "O"
*!* Is a root node. Out. This is my own rule,
*!* but if this check is skipped, the root nodes will work, too.
                RETURN
	ENDIF

	IF VARTYPE(THISFORM.TreePlanContabil.SELECTEDITEM.Previous) # "O"
*!* The selected node is the first child. No room to move up. Out.
		RETURN
	ENDIF

	LockWindowUpdate(THISFORM.HWND) && lock the window (api call)
	SELECT table
	LOCATE FOR iId = liCurrentKey
*!* Get the parent key for the selected node - I'll need it later
	liParentKey = table.iParentId
*!* Get the current position
	liCurrentPosition = table.iSortOrder
*!* Search the next record (cannot use Skip - they could be sorted somehow else)
	LOCATE FOR iParentKey = liParentKey AND iSortOrder = liCurrentPosition - 1
*!* Change the value in iSortOrder column
	REPLACE iSortorder WITH iSortorder + 1
*!* Go back to the first record
	LOCATE FOR iId = liCurrentKey
	REPLACE iSortOrder WITH iSortorder - 1
	TABLEUPDATE(.T.,.T.,"table")
	vp_parameter = some_specific_parameter && i use a parameterised view here, but no problem at all
	REQUERY("table")
	THISFORM.Filltree(.T.)
*!* This one fills the tree back, erasing all the nodes first - 
*!* that's .T. parameter stand for
	THISFORM.Tree.Nodes(liCurrentKey).EnsureVisible && just to keep it in window
	THISFORM.Tree.Nodes(liCurrentKey).SELECTED = .T. && I can click again on 'Move up' button
	LockWindowUpdate(0) && release the display lock
ENDIF

It works like a charm. It even could be optimized (for example, sort the nodes as the user wants and after that TABLEUPDATE()...

P.S. Can I give those three stars to myself? :)