Board index » cppbuilder » Using vsReport with a virtual-mode TListView

2005-11-01 07:53:30 PM
cppbuilder52
I'm trying to speed up a TListView by setting OwnerData true (to enable
virtual mode) in BCB5.
Generally speaking, things are going well (thanks to help from a BCB Journal
article from 2000), but I'm hitting a brick wall trying to implement proper
support for vsReport. I'm creating TListColumn instances at run-time and
setting their Width properties to ColumnHeaderWidth, but in virtual mode all
I get is columns that are all at position 0 (in the header control) with
Width -2.
Setting AutoSize true has no effect on the problem.
All the changes are in BeginUpdate-EndUpdate blocks, for both Items and
Columns.
If I use a 'real' width (i.e. not one of the constants -1 or -2) the columns
are fine.
Does anyone have any ideas? I'm not averse to handling listview WM_NOTIFYs
if need be, but if a simple change will let me use the VCL properties, it'll
save me a lot of time.
Many thanks,
GT
 

"Graham Thompson" < XXXX@XXXXX.COM >wrote in
message news:43675731$ XXXX@XXXXX.COM ...
not call ListView_SetColumnWidth() for vsReport when OwnerData is set to
True. You will have to call ListView_SetColumnWidth() manually after adding
your columns to the ListView.
Gambit
 

"Remy Lebeau (TeamB)" < XXXX@XXXXX.COM >wrote in message
suitable width myself using ListView_GetStringWidth() for each item to find
the widest 'cell'. I notice TCustomListView has a wrapper for it
(TCustomListView.StringWidth()) but doesn't appear to call it. I was hoping
to use TCustomListView.UpdateColumn() but that's where the '...not
OwnerData' condition kicks in, so that's a non-starter.
Thanks for the advice,
GT
 

{smallsort}

"Graham Thompson" < XXXX@XXXXX.COM >wrote in
message news: XXXX@XXXXX.COM ...
place, either. What you describe is handled by ColumnTextWidth instead.
In any case, as I mentioned earlier, you can simply call
TreeView_SetColumnWidth() yourself after adding your columns. Specify the
column's WidthType property as the width value. For example:
{
int NumColumns = 5;
for(int x = 0; x < NumColumns; ++x)
{
TListColumn *Column = ListView1->Columns->Add();
Column->Caption = "...";
Column->Width = ColumnHeaderWidth;
}
// needs to be done after all columns have been added,
// or else they are not sized properly...
for(int x = 0; x < NumColumns; ++x)
{
TListColumn *Column = ListView1->Columns->Items[x];
ListView_SetColumnWidth(ListView1->Handle, Column->Index,
Column->WidthType);
}
}
Gambit
 

"Remy Lebeau (TeamB)" < XXXX@XXXXX.COM >wrote in message
virtual-mode and ColumnHeaderWidth, and it worked exactly as it says on the
tin.
But ... the reason I went with ColumnHeaderWidth in the first place is that
I've always used it in design-time list views and columns have resized
themselves to which ever was the larger - column heading or content. I
stumbled across this by:
(a) Adding a listview in vsReport at design-time, with the
required number of columns. Each column had AutoSize false
and taLeftJustify.
(b) In the form's constructor, loop around the column collection
setting "ListView1->Column[iColumn]->Width = ColumnHeaderWidth"
Then, as long as more than one Item is added, the columns size as described.
I'd always assumed this was undocumented side-effect...
Anyway - back to the virtul-mode TListView, I'll look into the column
dragging etc. too, since it looks like I might need to do a little
double-buffering...
Thanks once again Remy,
GT