function InputCombo(const ACaption, APrompt: string; const AList: TStrings): string;
 
function GetCharSize(Canvas: TCanvas): TPoint;
var
I: Integer;
Buffer: array[0..51] of Char;
begin
for I := 0 to 25 do Buffer[I] := Chr(I + Ord('A'));
for I := 0 to 25 do Buffer[I + 26] := Chr(I + Ord('a'));
GetTextExtentPoint(Canvas.Handle, Buffer, 52, TSize(Result));
Result.X := Result.X div 52;
end;  
 
var
Form: TForm;
Prompt: TLabel;
Combo: TComboBox;
DialogUnits: TPoint;
ButtonTop, ButtonWidth, ButtonHeight: Integer;
begin
Result := '';
Form   := TForm.Create(Application);
with Form do
try
Canvas.Font := Font;
DialogUnits := GetCharSize(Canvas);
BorderStyle := bsDialog;
Caption     := ACaption;
ClientWidth := MulDiv(180, DialogUnits.X, 4);
Position    := poScreenCenter;
Prompt      := TLabel.Create(Form);
with Prompt do
begin
Parent   := Form;
Caption  := APrompt;
Left     := MulDiv(8, DialogUnits.X, 4);
Top      := MulDiv(8, DialogUnits.Y, 8);
Constraints.MaxWidth := MulDiv(164, DialogUnits.X, 4);
WordWrap := True;
end;
Combo := TComboBox.Create(Form);
with Combo do
begin
Parent := Form;
Style  := csDropDownList; // Caso o item possa ser digitado, altere aqui para csDropDowns
Items.Assign(AList);
ItemIndex := 0;
Left      := Prompt.Left;
Top       := Prompt.Top + Prompt.Height + 5;
Width     := MulDiv(164, DialogUnits.X, 4);
end;
ButtonTop    := Combo.Top + Combo.Height + 15;
ButtonWidth  := MulDiv(50, DialogUnits.X, 4);
ButtonHeight := MulDiv(14, DialogUnits.Y, 8);
with TButton.Create(Form) do
begin
Parent      := Form;
Caption     := 'OK';
ModalResult := mrOk;
default     := True;
SetBounds(MulDiv(38, DialogUnits.X, 4), ButtonTop, ButtonWidth,
ButtonHeight);
end;
with TButton.Create(Form) do
begin
Parent      := Form;
Caption     := 'Cancelar';
ModalResult := mrCancel;
Cancel      := True;
SetBounds(MulDiv(92, DialogUnits.X, 4), Combo.Top + Combo.Height + 15,
ButtonWidth, ButtonHeight);
Form.ClientHeight := Top + Height + 13;
end;
if ShowModal = mrOk then
begin
Result := Combo.Text;
end;
finally
Form.Free;
end;
end;

procedure Tfrmproduto_pedido.BtnImprimirClick(Sender: TObject);
var
List: TStringList;
vResult : String;
indice : Integer;
begin
 
try
List := TStringList.Create;
List.Add('Sem Preço');
List.Add('Com Preço');
 
//Rseultado string do item selecionado
vResult := InputCombo('Seleciona o tipo de relatório', 'Descrição:', List);
 
// Se quiser o indice selecionado por fazer o seguinte
indice := List.IndexOf(vResult);
finally
List.Free;
end;
 
// Testando o retorno string
if (vResult = 'Sem Preço') then
begin
ShowMessage('Sem Preço');
end;
 
if (vResult = 'Com Preço') then
begin
ShowMessage('Com Preço');
end;
 
// Testando o retorno Integer
ShowMessage( List[ indice ]  );
end;