Monday, June 25, 2007

Adding TCheckbox to TCombobox

You need to do the following:

Set ComboBox.Style:=csOwnerDrawFixed

//..... your form class
private
Selected: array of Boolean;
//.....


procedure TForm1.ComboBox1DrawItem(Control: TWinControl;
Index: Integer; Rect: TRect; State: TOwnerDrawState);
begin
SetLength(Selected, TComboBox(Control).Items.Count);
with TComboBox(Control).Canvas do
begin
FillRect(rect);

Rect.Left := Rect.Left + 1;
Rect.Right := Rect.Left + 13;
Rect.Bottom := Rect.Bottom;
Rect.Top := Rect.Top;

if not (odSelected in State) and (Selected[Index]) then
DrawFrameControl(Handle, Rect, DFC_BUTTON,
DFCS_BUTTONCHECK or DFCS_CHECKED or DFCS_FLAT)
else if (odFocused in State) and (Selected[Index]) then
DrawFrameControl(Handle, Rect, DFC_BUTTON,
DFCS_BUTTONCHECK or DFCS_CHECKED or DFCS_FLAT)
else if (Selected[Index]) then
DrawFrameControl(Handle, Rect, DFC_BUTTON,
DFCS_BUTTONCHECK or DFCS_CHECKED or DFCS_FLAT)
else if not (Selected[Index]) then
DrawFrameControl(Handle, Rect, DFC_BUTTON, DFCS_BUTTONCHECK or DFCS_FLAT);

TextOut(Rect.Left + 15, Rect.Top, TComboBox(Control).Items[Index]);
end;
end;

procedure TForm1.ComboBox1Select(Sender: TObject);
var
i: Integer;
Sel: string;
begin
Sel := EmptyStr;
Selected[TComboBox(Sender).ItemIndex] := not Selected[TComboBox(Sender).ItemIndex];
for i := 0 to TComboBox(Sender).Items.Count - 1 do
if Selected[i] then
Sel := Sel + TComboBox(Sender).Items[i] + ' ';
ShowMessage(Sel); //Just for test...
end;

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