How to insert automatic values to an edit component if a checkbox is checked

Question

I have an edit1 and some checkbox1 upto checkbox6 in a form. I want to insert values in edit1 component such as january when checkbox1 is clicked, february when checkbox2 is clicked... upto june for checkbox6. If a checkbox is unchecked, edit1 should not have the corresponding value. If for instance checkbox1, checkbox2 and checkbox3 are checked, I should have values like January february march in edit1. However, if I uncheck checkbox2, values in edit1 should be january and march. If none of the checkbox is checked, then edit1 should not have any values. How do i do this in Delphi 7?

Answer 1

Assign a single OnClick event handler to all 6 TCheckBox controls, and have it check all 6 TCheckBox states and update the TEdit accordingly, eg:

procedure TMyForm.CheckBoxClick(Sender: TObject);
var
  S: String;

  procedure IncludeMonth(const MonthName: String);
  begin
    if S <> '' then
      S := S + ', ' + MonthName
    else
      S := MonthName;
  end;

begin
  if CheckBox1.Checked then IncludeMonth('January');
  if CheckBox2.Checked then IncludeMonth('February');
  if CheckBox3.Checked then IncludeMonth('March');
  if CheckBox4.Checked then IncludeMonth('April');
  if CheckBox5.Checked then IncludeMonth('May');
  if CheckBox6.Checked then IncludeMonth('June');
  Edit1.Text := S;
end;

Alternatively:

procedure TMyForm.CheckBoxClick(Sender: TObject);
var
  Months: TStringList;
begin
  Months := TStringList.Create;
  try
    if CheckBox1.Checked then Months.Add('January');
    if CheckBox2.Checked then Months.Add('February');
    if CheckBox3.Checked then Months.Add('March');
    if CheckBox4.Checked then Months.Add('April');
    if CheckBox5.Checked then Months.Add('May');
    if CheckBox6.Checked then Months.Add('June');
    Edit1.Text := Months.CommaText;
  finally
    Months.Free;
  end;
end;