What is the default value of 'Text' parameter in TField.OnGetText

Question

I have a procedure attached to TField.OnGetText event of field Score like this:

procedure TMyForm.GetScoreText(Sender: TField; var Text: string; DisplayText: Boolean);
begin
    if StrToInt(Sender.AsString) >= 80 and StrToInt(Sender.AsString) <= 100 then
        Text := 'Great!';
    else if StrToInt(Sender.AsString) >= 60 and StrToInt(Sender.AsString) < 80 then
        Text := 'Good';
end;

From OnGetText documentation, I know that when there is no OnGetText handler defined, the Text property of the field is the name as AsString property. But my question is, what value does the var parameter Text get there is an OnGetText defined but the the Text is defined for the current value of the field. That is in my case, what value does the Text get when value of the field Score is something less than 60? Is it Null, or empty string, or something else? I need to know it explicitly because there is some logic that depends on the value being displayed.

I learned from this SO post that there was nothing being displayed for the field when the OnGetText handler procedure has no code, that is body of the procedure is empty.

Answer 1

When an OnGetText assigned and nothing returns in the Text argument, then the result is an empty string.

Look at the Db source:

function TField.GetDisplayText: string;
begin
  Result := '';
  if Assigned(FOnGetText) then
    FOnGetText(Self, Result, True) else
    GetText(Result, True);
end;

The Result initially is set to an empty string and passes it to the FOnGetText if it was assigned.