Delphi XE8: HTTPEncode convert string error - delphi

Question

I use the HTTPEncode() function in Delphi XE8 to encode Japanese text. Some characters can encode correctly, but some cannot. Below is an example:
aStr := HTTPEncode('萩原小学校');
I expected this:
aStr = '%E8%90%A9%E5%8E%9F%E5%B0%8F%E5%AD%A6%E6%A0%A1'
But I got this:
aStr = '%E8%90%A9%E5%8E%9F%E5%B0%8F%3F%E6%A0%A1'
Can someone help me to encode '萩原小学校' as '%E8%90%A9%E5%8E%9F%E5%B0%8F%E5%AD%A6%E6%A0%A1'?

Answer 1

I'm not sure what this HTTPEncode function is. There is a function in Web.HTTPApp of that name. Perhaps that is what you refer to. If so, it is clearly marked as deprecated. Assuming you have enabled compiler warnings, the compiler will be telling you this, and telling you also to use TNetEncoding.UTL.Encode instead.
Let's try that:
{$APPTYPE CONSOLE}
uses
System.NetEncoding;
begin
Writeln(TNetEncoding.URL.Encode('萩原小学校'));
end.
Output
%E8%90%A9%E5%8E%9F%E5%B0%8F%E5%AD%A6%E6%A0%A1

Answer 2

# David Heffernan, # Remy Lebeau, thank you so much for your time to help me. your answer make me understand why i cannot convert my string with HTTPEncode.
I have tried many times myself till i found this: Delphi: Convert from windows-1251 to Shift-JIS
function MyEncode(const S: string; const CodePage: Integer): string;
var
Encoding: TEncoding;
Bytes: TBytes;
b: Byte;
sb: TStringBuilder;
begin
Encoding := TEncoding.GetEncoding(CodePage);
try
Bytes := Encoding.GetBytes(S);
finally
Encoding.Free;
end;
sb := TStringBuilder.Create;
try
for b in Bytes do begin
sb.Append('%');
sb.Append(IntToHex(b, 2));
end;
Result := sb.ToString;
finally
sb.Free;
end;
end;
MyEncode('萩原小学校', 65001);
Output = %E8%90%A9%E5%8E%9F%E5%B0%8F%E5%AD%A6%E6%A0%A1