Mega Code Archive
Checklistboxes
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Indicates which items are checked.
type TCheckBoxState = (cbUnchecked, cbChecked, cbGrayed);
property State[Index: Integer]: TCheckBoxState;
Description
For each member of the Items array, State indicates
whether its check box is selected (cbChecked), deselected
(cbUnchecked), or grayed (cbGrayed). The cbChecked state
corresponds to the Boolean property Checked; that is,
State = cbChecked when Checked = True.
To add lines to the CheckListBox:
CheckListBox.Items.Add('Next line');
To put a BitMap next to each string in a CheckListBox:
EXAMPLE:
Here is a typical handler for an OnDrawItem event.
In the example, a list box with the lbOwnerDrawFixed style
draws a bitmap to the left of each string.
procedure TForm1.ListBox1DrawItem(Control: TWinControl; Index: Integer;
Rect:TRect;State: TOwnerDrawState);
var
Bitmap: TBitmap; { temporary variable for the item’s bitmap }
Offset: Integer; { text offset width }
begin
with (Control as TListBox).Canvas do { draw on control canvas, not on the form }
begin
FillRect(Rect); { clear the rectangle }
Offset := 2; { provide default offset }
Bitmap := TBitmap((Control as TListBox).Items.Objects[Index]); { get the bitmap )
if Bitmap <> nil then
begin
BrushCopy(Bounds(Rect.Left + 2, Rect.Top, Bitmap.Width, Bitmap.Height),
Bitmap, Bounds(0, 0, Bitmap.Width, Bitmap.Height), clRed); {render bitmap}
Offset := Bitmap.width + 6; { add four pixels between bitmap and text}
end;
TextOut(Rect.Left + Offset, Rect.Top, (Control as TListBox).Items[Index]) { display the text }
end;
end;
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