What I'd suggest is delving into the code where GetTopItem Event is called and find the location where this is set. Rather than trying to identify a scroll, it sounds like a change in the topviewitem is going to provide the same trigger.<br>
<br><div class="gmail_quote">On Fri, Feb 25, 2011 at 3:08 PM, David O'Brien <span dir="ltr"><<a href="mailto:Dave@iccs.co.nz">Dave@iccs.co.nz</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div link="blue" vlink="purple" lang="EN-NZ"><div><p class="MsoNormal"><span style="font-size: 11pt;">I am working on an application (D2009) where I need to know when a TListView is Scrolled.</span></p><p class="MsoNormal">
<span style="font-size: 11pt;">I have used Application.OnMessage to look for WM_VScroll messages, but they do not happen, also have tried creating the below which I thought should work:</span></p><p class="MsoNormal"><span style="font-size: 11pt;"> </span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> TLVScrollEvent = procedure(Sender: TObject) of object;</span></p><p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> </span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> TICListView = class(TListView)</span></p><p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> private</span></p><p class="MsoNormal">
<span style="font-size: 11pt; color: rgb(31, 73, 125);"> FOnScroll: TLVScrollEvent;</span></p><p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> protected</span></p><p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> Procedure WMVScroll( Var Msg: TMessage ); message WM_VSCROLL;</span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> Procedure WMHScroll( Var Msg: TMessage ); message WM_HSCROLL;</span></p><p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> property OnScroll: TLVScrollEvent read FOnScroll write FOnscroll ;</span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> end;</span></p><p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> </span></p><p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);">procedure Register ;</span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> </span></p><p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);">implementation</span></p><p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> </span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);">procedure Register;</span></p><p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);">begin</span></p><p class="MsoNormal">
<span style="font-size: 11pt; color: rgb(31, 73, 125);"> RegisterComponents('Dave', [TICListView]);</span></p><p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);">end;</span></p><p class="MsoNormal">
<span style="font-size: 11pt; color: rgb(31, 73, 125);"> </span></p><p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);">procedure TICListView.WMHScroll(var Msg: TMessage);</span></p><p class="MsoNormal">
<span style="font-size: 11pt; color: rgb(31, 73, 125);">begin</span></p><p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> OnScroll ;</span></p><p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> inherited;</span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);">end;</span></p><p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> </span></p><p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);">procedure TICListView.WMVScroll(var Msg: TMessage);</span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);">begin</span></p><p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> OnScroll ;</span></p><p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> inherited;</span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);">end;</span></p><p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> </span></p><p class="MsoNormal"><span style="font-size: 11pt;">which also doesn’t fire. I have written a list of all messages fired when the scrollbar is moved, but there doesn’t seem to be anything useful…</span></p>
<p class="MsoNormal"><span style="font-size: 11pt;"> </span></p><p class="MsoNormal"><span style="font-size: 11pt;">Anyone have a solution?</span></p><p class="MsoNormal"><span style="font-size: 11pt;"> </span></p><p class="MsoNormal">
<span style="font-size: 11pt;">Regards,</span></p><p class="MsoNormal"><span style="font-size: 11pt;">Dave.</span></p></div></div><br>_______________________________________________<br>
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