Mega Code Archive
TListBox Ellipsis (without creating a new component)
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Title: TListBox Ellipsis (without creating a new component)
Question: How do you modify an existing TListBox, adding an ellipsis (...) to item strings that are too long to fit within the control, without creating a new component?
Answer:
This fast and simple way utilizes Borland's own DrawItem code, with a simple modification
to incorporate an additional WinAPI flag: DT_END_ELLIPSIS
Steps taken:
1. Change the TListBox.Style to lbOwnerDrawFixed (causes OnDrawItem event to fire)
2. Modify the TListBox.OnDrawItem event as follows
procedure TForm1.ListBox1DrawItem(Control: TWinControl; Index: Integer;
Rect: TRect; State: TOwnerDrawState);
var
Flags: Longint;
begin
with TListBox(Control) do
begin
Canvas.FillRect(Rect);
if Index then
begin
Flags := DrawTextBiDiModeFlags(DT_SINGLELINE or DT_VCENTER or
DT_NOPREFIX or DT_END_ELLIPSIS);
if not UseRightToLeftAlignment then
Inc(Rect.Left, 2)
else
Dec(Rect.Right, 2);
DrawText(Canvas.Handle, PChar(Items[Index]), Length(Items[Index]), Rect,
Flags);
end;
end;
end;
Additionally, if an item string contains backslash characters, you can use the DT_PATH_ELLIPSIS
flag to replace characters in the middle of the string (commonly used with long filenames).
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