Question

I’m trying to create an edit box and I want it to be able to auto-append the text entered while typing. Text would be appended with “suggestions” from a text file.

Let’s say I have these in my suggestion file:
Marilyn Monroe
Marlon Brando
Mike Myers

As I start typing “M” in the edit box, the remaining would appear highlighted(or not):
“arilyn Monroe”
And as I keep typing “Mi” then “ke Myers” would appear at the end. I hope I’m making this clear enough for you guys! Thanks for your help!

Answer 1

You can implement this feature easily using a TComboBox.

follow these steps :

• drop a combobox in your form
• set the autocomplete property to true
• set the sorted property to true
• set the style property to csDropDown
• in the OnExit event of the combobox add a code like this

const
MaxHistory=200;//max number of items


procedure TForm1.ComboBoxSearchExit(Sender: TObject);
begin
   //check if the text entered exist in the list, if not add to the list
   if (Trim(ComboBoxSearch.Text)<>'') and (ComboBoxSearch.Items.IndexOf(ComboBoxSearch.Text)=-1) then 
   begin
     if ComboBoxSearch.Items.Count=MaxHistory then
     ComboBoxSearch.Items.Delete(ComboBoxSearch.Items.Count-1);
     ComboBoxSearch.Items.Insert(0,ComboBoxSearch.Text);
   end;
end;

• Save the History of your combobox , for example in the OnClose event of your
  form

procedure TForm1.FormClose(Sender: TObject);
begin
   ComboBoxSearch.Items.SaveToFile(ExtractFilePath(ParamStr(0))+'History.txt');
end;

• in the Oncreate event of your form you can load the saved items

procedure TForm1.FormCreate(Sender: TObject);
var
 FileHistory  : string;
begin
   FileHistory:=ExtractFilePath(ParamStr(0))+'History.txt';
   if FileExists(FileHIstory) then
   ComboBoxSearch.Items.LoadFromFile(FileHistory);
end;