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Shawn Lammers · Guest

In Builder 5 I am using a TListView component to create a report form. This
component allows for multiple coulmns that can be re-sized by draging the
column separetor.

There is a colum resize feature that I want to change. If you double click
on the column separator the column automatically resizes to the size of that
columns longest data item. However, I want it to resize to the longest data
item OR the column header text, which ever is longer.

Can someong explain how I would create a decendant from CustomListView to
add this ability?

In the VCL source for ComCtrls I found this bit of code

procedure TCustomListView.WMNotify(var Message: TWMNotify);
var
Col: TListColumn;
P: TPoint;
hChildWnd: HWND;
WndClass: string;
hdhti: THDHitTestInfo;
begin
inherited;
if ValidHeaderHandle and (Message.NMHdr^.hWndFrom = FHeaderHandle) then
with Message.NMHdr^ do
case code of
HDN_ENDTRACK:
with PHDNotify(Pointer(Message.NMHdr))^, PItem^ do
if (Mask and HDI_WIDTH) <> 0 then
begin
Col := GetColumnFromTag(Item);
if Col.MinWidth >= cxy then
cxy := Col.MinWidth
else if (Col.MaxWidth > 0) and (Col.MaxWidth <= cxy) then
cxy := Col.MaxWidth;
Col.Width := cxy;
end;
HDN_ENDDRAG:
FUpdatingColumnOrder := True;
HDN_DIVIDERDBLCLICK:
with PHDNotify(Pointer(Message.NMHdr))^ do
begin
Col := GetColumnFromTag(Item);
Col.Width := ListView_GetColumnWidth(Handle, Item);
if IsCustomDrawn(dtControl, cdPrePaint) then Invalidate;
end;

I figure the case for HDN_DIVIDERDBLCLICK is what is implementing this
function. But how do you create a new control that overrides this
functionality?

Thanks
Shawn