select more than one checkbox to execute condition - windows

Question

I want a text file to show contents in memo1 once I have selected 2 checkboxes.
How would I do this?
I tried the code below but I can't seem to get it right.
if CheckBox1.Checked and CheckBox2.Checked then
begin
memo1.lines.LoadFromFile('files\RS.txt');
end;
I also want to be able to select the checkboxes individually Like:
(pointing this out in case combining them prevents checking them individually)
Checkbox1:
procedure TForm1.CheckBox1Change(Sender: TObject);
begin
memo1.lines.LoadFromFile('files\R.txt');
end;
Checkbox2:
procedure TForm1.CheckBox2Change(Sender: TObject);
begin
memo1.lines.LoadFromFile('files\S.txt');
end;
Any suggestions/Improvements will be appreciated.
Running Lazarus IDE v1.6.4
Windows 10 x64

Answer 1

I'm assuming your objective is to generate a filename which depends on the
particular combination of the boolean states of the two checkboxes -
see example code below. The point of doing this is that it helps separate
the definition of what you want the file name to be from what you want to do
with it.
procedure TForm1.Button1Click(Sender: TObject);
begin
Memo1.Lines.LoadFromFile(GetFileName);
end;
function TForm1.GetFileName: String;
begin
// Return empty string if neither checkbox is checked
Result := '';
if Checkbox1.Checked and Checkbox2.Checked then
Result := 'files\RS.txt'
else // if we reach here only one of the checkboxes, or neither, is checked
if Checkbox1.Checked then
Result := 'files\R.txt'
else
if Checkbox2.Checked then
Result := 'files\S.txt'
end;
I've assigned an empty string to the Result of the function at the outset to ensure that the Result is always defined.
Important You'll notice that the above does not use the Change events of the Checkboxes. The reason is that you may not get the result you need (or are expecting) if the Change events are never triggered - for example if one CheckBox is set to Checked in the IDE but the other isn't, and you want to get the right file name regardless of whether the user has actually clicked either one of them.

Answer 2

As far as I understood you want the following behaviour:
There are two check boxes
There is one memo field
Depending on the state of the two check boxes the text in the memo field shall change
If this understanding is correct:
I typically don't use Pascal but your problem seems to be independent of the programming language used. I would do it like this:
The two procedures TForm1.CheckBox1Change and TForm1.CheckBox2Change are called whenever the corresponding check box'es state changes.
I would write a third procedure and call this third procedure from both procedures. I would do nothing else than calling this third procedure in the other two procedures.
In the third procedure I would evaluate what to do - depending on the state of both check boxes.

Answer 3

A separate checkboxchange proocedure per event is automatically generated by the designer if you double click the event. However that is not a rigid decision.
If you have the initial codefragment in e.g. checkbox1change, you can simply point the onchange of checkbox2 to that existing checkbox1change by using the dropdown of the onchange of checkbox2