Set ComboBox text on selection - delphi

Question

I am working on an application where i have a combobox with long text values.Since the text values are large(in term of characters ..20 or more), to display in the combobox, the requirement was to display on the first character after selecting from the drop down.
Like in the image marked in red. if the user selects 3th item 3 0.5 to 1.25 Slight i should only display the 3 in the combobox.
So i tried this
sTheSelectedValue : string;
procedure TForm1.ComboBox1Select(Sender: TObject);
begin
sTheSelectedValue:=TrimTextAndDisplay(ComboBox1.Text); //send theselected value
ComboBox1.Text :=''; //clear the selection
ComboBox1.Text:=sTheSelectedValue; //now assign as text to combo box
Button1.Caption:=ComboBox1.Text; //just show the new value on the button.
end;
function TForm1.TrimTextAndDisplay(TheText : string): string;
var
sTheResult : string;
begin
sTheResult :=copy(TheText,0,1); //extract the first value..
Result :=sTheResult;
end;
The result is
The button seem to show the proper value but not the combobox.
what i want is to get 3 in the combobox, i cant seem set ComboBox1.Text:=
can any one tell me how to do it?
like this on selection of from the combobox the result should be

Answer 1

I would suggest owner-drawing the ComboBox to handle this. Set the TComboBox.Style property to csOwnerDrawFixed, then store just the numbers '1', '2', '3', etc in the TComboBox.Items property itself and use the TComboBox.OnDrawItem event to render the full strings when the drop-down list is visible, eg:
var
sTheSelectedValue : string;
const
ItemStrings: array[0..7] of string = (
'0 to 0.1 Calm (rippled)',
'0.1 to 0.5 Smooth (wavelets)',
'0.5 to 1.25 Slight',
'1.25 to 2.5 Moderate',
'2.5 to 4 Rough',
'4 to 6 Very rough',
'6 to 9 High',
'9 to 14 Very high');
procedure TForm1.FormCreate(Sender: TObject);
var
I: Integer;
begin
ComboBox1.Items.BeginUpdate;
try
for I := Low(ItemStrings) to High(ItemStrings) do begin
ComboBox1.Items.Add(IntToStr(I+1));
end;
finally
ComboBox1.Items.EndUpdate;
end;
end;
procedure TForm1.ComboBox1Select(Sender: TObject);
begin
sTheSelectedValue := IntToStr(ComboBox1.ItemIndex+1);
Button1.Caption := sTheSelectedValue;
end;
procedure TForm1.ComboBox1DrawItem(Control: TWinControl; Index: Integer; Rect: TRect; State: TOwnerDrawState);
var
s: String;
begin
if odSelected in State then begin
ComboBox1.Canvas.Brush.Color := clHighlight;
ComboBox1.Canvas.Font.Color := clHighlightText;
end else begin
ComboBox1.Canvas.Brush.Color := ComboBox1.Color;
ComboBox1.Canvas.Font.Color := ComboBox1.Font.Color;
end;
ComboBox1.Canvas.FillRect(Rect);
s := IntToStr(Index+1);
if not (odComboBoxEdit in State) then begin
s := s + ' ' + ItemStrings[Index];
end;
ComboBox1.Canvas.TextRect(Rect, Rect.Left+2, Rect.Top+2, s);
if (State * [odFocused, odNoFocusRect]) = [odFocused] then begin
ComboBox1.Canvas.DrawFocusRect(Rect);
end;
end;

Answer 2

You have to try to save the data in a record, for ex:
type
TMyRec = record
Num:Integer;
Text:String;
end;
TMyRecArray = array of TMyRec;
MyRecArray:TMyRecArray;
then you can set manually the items to be set in the ComboBox (on the OnFromCreate),
SetLength(MyRecArray,9);
MyRecArray[0].Num:=1;
MyRecArray[0].Text:='0 to 0.1 Calm Rippled';
.
.
and so on.
then in the combobox strigns place only the numbers, and
procedure TForm1.ComboBox1Select(Sender: TObject);
var
i:integer;
begin
for i:=0 to 9 do
begin
if ComboBox1.Text=IntToStr(MyRecArray[i].Num) then
Button1.Caption:=MyRecArray[i].Text;
end;
end;