Setting ComboBox text when selecting

Question

I am working on an application that has a summary with long text values. Since the text values ​​are large (in the form of characters. 20 or more) to display in the drop-down list, the requirement was to display on first after selecting from the drop-down list. Like the image marked in red. if the user selects the 3rd element 3 0.5 to 1.25 Slight , I should only display 3 in the combo box.

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; 

Result

The button seems to show the correct value, but not the combo box.

I want to get 3 in the drop down list, I can’t configure ComboBox1.Text:= can someone tell me how to do this? for example, when choosing from the drop-down list, the result should be

Answer 1

I would suggest creating a ComboBox drawing for this. Set the csOwnerDrawFixed property to csOwnerDrawFixed , then save only the numbers '1' , '2' , '3' , etc. In the TComboBox.Items property and use the TComboBox.OnDrawItem event to display full lines when you see a drop-down list, for example:

 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 need to try to save the data in a record, for example:

  type TMyRec = record Num:Integer; Text:String; end; TMyRecArray = array of TMyRec; MyRecArray:TMyRecArray; 

then you can manually set the elements to be installed in the ComboBox ( in OnFromCreate ),

 SetLength(MyRecArray,9); MyRecArray[0].Num:=1; MyRecArray[0].Text:='0 to 0.1 Calm Rippled'; . . 

etc.

then in the combobox lists only numbers are indicated, 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;