Assign Font From TComboBox D7 - delphi

Question

Delphi v7
Let me preface my remedial question by saying that I am not a real programer. I am a Deputy Sheriff and I write an occasional project to help us do what we do.
My current project contains several TDBRichEdit controls. I have assigned various formatting processes to toolbar buttons. I would like to be able to change the RichEdit font using a ComboBox. The combobox is populated with the font list, but it does not affect the font of the TDBRichEdit control. I have been trying to figure this out for over a week and I cannot see the problem.
This is what I have done:
Form OnCreate procedure
procedure TForm1.FormCreate(Sender: TObject);
begin
PageControl1.ActivePage:= TabSheet1;
GetFontNames;
SelectionChange(Self);
CurrText.Name := DefFontData.Name;
CurrText.Size := -MulDiv(DefFontData.Height, 72, Screen.PixelsPerInch);
end;
Form Selection Change
procedure TForm1.SelectionChange(Sender: TObject);
begin
if ActiveControl is TDBRichEdit then
with ActiveControl as
TdbRichEdit do begin
try
Ctrlupdating := True;
Size.Text := IntToStr(SelAttributes.Size);
cmbFont.Text := SelAttributes.Name;
finally
Ctrlupdating := False;
end;
end;
end;
Functions (Except for the "ActiveControl part these are not my functions and I don't have enough knowledge to completely understand them.)
Function TForm1.CurrText: TTextAttributes;
begin
if ActiveControl is TDBRichEdit then
with ActiveControl as
TdbRichEdit do begin
if SelLength > 0 then Result := SelAttributes
else Result := DefAttributes;
end;
end;
function EnumFontsProc(var LogFont: TLogFont; var TextMetric: TTextMetric;
FontType: Integer; Data: Pointer): Integer; stdcall;
begin
TStrings(Data).Add(LogFont.lfFaceName);
Result := 1;
end;
OnDraw event of the combobox
procedure TForm1.cmbFontDrawItem(Control: TWinControl; Index: Integer;
Rect: TRect; State: TOwnerDrawState);
begin
with (Control as TComboBox).Canvas do
begin
Font.Name := Screen.Fonts.Strings[Index];
FillRect(Rect) ;
TextOut(Rect.Left, Rect.Top, PChar(Screen.Fonts.Strings[Index]));
end;
end;
OnChange event for the combobox
procedure TForm1.cmbFontChange(Sender: TObject);
begin
if Ctrlupdating then Exit;
CurrText.Name := cmbFont.Items[cmbFont.ItemIndex];
end;
Any Ideas?

Answer 1

In your code you try to modify the text attributes in this code:
procedure TForm1.cmbFontChange(Sender: TObject);
begin
if Ctrlupdating then Exit;
CurrText.Name := cmbFont.Items[cmbFont.ItemIndex];
end;
When this code executes, ActiveControl will be cmbFont. Now look at CurrText.
if ActiveControl is TDBRichEdit then
with ActiveControl as TdbRichEdit do
begin
if SelLength > 0 then
Result := SelAttributes
else
Result := DefAttributes;
end;
So, the first if block will not be entered.
In fact your function appears not to assign anything to Result in this case. You must always assign to Result. The compiler will tell you this when you enable warnings and hints.
Instead of using ActiveControl you should specify the rich edit instance directly. I don't know how your form is arranged, but you'll need to use some other means to work out which rich edit control the change is to be applied to. Perhaps based on the active page of the page control.

Answer 2

I managed to get the combobox working. My code is probably very awkward, but it works. Thank you for your help. I would not have been able to solve this problem without it.
I wrote a separate function for each of the richedit contols. With FormCreate I had to add lines for each of the functions
procedure TForm1.FormCreate(Sender: TObject);
begin
PageControl1.ActivePage:= TabSheet1;
GetFontNames;
SelectionChange(Self);
**CurrText.Name := DefFontData.Name;
CurrText.Size := -MulDiv(DefFontData.Height, 72, Screen.PixelsPerInch);**
end;
In SelectionChange I had to make a call to the PARAGRAPH attributes of the rich edit control. I was not able to do that collectively. I addressed the rich edit control “reProc” only. The others seem to work fine with that one line. I would like to understand that one.
Form Selection Change
procedure TForm1.SelectionChange(Sender: TObject);
begin
if ActiveControl is TDBRichEdit then
with reProc.Paragraph do begin
try do begin
You gave me the idea. I was not able to address all the richedit controls collectively, so I wrote a function for each of the richedit controls separately.
function TForm1.CurrText: TTextAttributes;
begin
if reProc.SelLength > 0 then Result := reProc.SelAttributes
else Result := **reProc.DefAttributes;**
For the OnChange event for the combobox I had to add lines for each of the functions
procedure TForm1.cmbFontChange(Sender: TObject);
begin
if Ctrlupdating then Exit;
**CurrText.Name := cmbFont.Items[cmbFont.ItemIndex];**
end;