Delphi XE3, unicode & utf-8?

Question

Delphi

Good afternoon.
For the third day I've been struggling with the following task:
There is a template - an html-file in utf-8 encoding and a form on which, conditionally, there are several TEdit components.
All you need to do is to replace the string "{{ edit1 }}" in the template with the content of Edit.Text and save the resulting file back to utf-8.
It would seem that the task of replacing a substring in a string is, but no: a problem with encodings. No matter how hard I try, “non-standard” characters like ü and ö are lost .
Tried many ways:

// template: TStringList, в котором хранится содержимое файла template.html
        for i:=0 to template.Count-1 do
            begin
                 s:=template.Strings[i];
                 s:=StringReplace(s,'{{ edit1 }}',Edit1.Text,[rfReplaceAll,rfIgnoreCase]);
                 s:=StringReplace(s,'{{ edit2 }}',Edit2.Text,[rfReplaceAll,rfIgnoreCase]);
                 WS:=s; // пробовал и так
                 WriteFile(HF,PChar(WS)^,Length(WS)*2,D, nil);
                 //writeln(f,s); // и так
            end;

either umlauts are lost from the template or from edits ( ü becomes u ).
I also tried this option - manually overtake encodings:

var
   s,s8:UTF8String;
   s2:string;
   fi,fo:textfile;
   l:integer;
begin
     AssignFile(fi,'template8.html');
     AssignFile(fo,'result.html');
     Reset(fi);
     Rewrite(fo);
     while not EoF(fi) do
           begin
                readln(fi,s);
                s2:=UTF8ToUnicodeString(s);
                l:=length(s2);
                SetLength(s8,l*SizeOf(Char)+1);
                UnicodeToUtf8(PAnsiChar(s8),length(s8),PWideChar(s2),l);
                writeln(fo,s8);
           end;
     CloseFile(fi);
     CloseFile(fo)
end;

But it doesn't work.
Maybe someone faced similar? In which direction to dig?
Thank you.

Answer 1

There shouldn't be a problem. Throw off the finished code of the minimum size, where your problem manifests itself.

Answer 2

Time passes, but the problems are the same...
The problem is in the incorrect operation of the component code. The problem with encodings is observed in a number of standard components of the Delphi environment after version 7. There is only one solution (of which I know) - to replace the problematic components with components where there will be no problem with encodings. You can also roll back the project to version 7.