You cannot uncheck checkbox from within of a treeview. See Treeview - programmatically UNcheck a mouse-checked node Message #731673

Also there's no need to make code more complicated that it should be.

* This convoluted expression
toNode.Checked = !toNode.Checked=.t.
* Is the same as simple
toNode.Checked = !toNode.Checked

	Select mytableA
	Set Order To client_id
	Seek toNode.Tag
	If  Found() ...
* can be shortened to
	If SEEK(toNode.Tag, "mytableA", "client_id") ...
<pre>

>
>at mytreeview.nodecheck method I'm trying to:<pre>*** ActiveX Control Event ***
>Lparameters toNode
>This.SelectedItem = toNode
>If  Empty(toNode.Tag)
>	Thisform.actionrecursive_in_child( toNode )
>Else
>	Select mytableA
>	Set Order To client_id
>	Seek toNode.Tag
>	If  Found() and !Empty(clients.email)
>	    toNode.Checked = !toNode.Checked=.t. && seems doing fine
>	Else
>        	    toNode.Checked = .f.   && here is the point... uncheck fine here.
>	    *This.SelectedItem.Checked = .f.
>	*   ?? CHR(07)
>	*   ThisForm.Container1.Text10.SetFocus()
>	*	NODEFAULT 
>                *	RETURN .f.
>	Endif
>Endif
>

>
>My goal is about to doesn't allow the user check items with empty field of client's email...
>
>So, if I Follow this code with debug... it run and does fine what I'm trying to do... But after notecheck method it becomes checked again with no logic reason.
>
>Is there a way, on treeview, to allow check only in some sort of data??
>
>TIATOALL
>
>Claudio