Delphi7 Canvas.TextOut can't write new lines

问题

I am trying to replace all "#" with new lines to draw:

Canvas.TextOut(0,0,''+StringReplace('a#b','#',#13#10,[rfReplaceAll]));

but nothing.
TextOut prints "a#b" like the the replaced part doesn't even exist (But it does exist ofcourse): ab
Instead of this:

a
b

#13#10 is the new line (Windows) right?
Then why this isn't working?

Thank you.

回答1:

You need to use DrawText to produce multi-line text:

var
  R: TRect;
....
R := Rect(0, 0, Width, Height);
DrawText(
  Canvas.Handle,
  PChar(StringReplace('a#b','#',#13#10,[rfReplaceAll])),
  -1,
  R,
  0
);

You may very well want to use different flags in the final parameter, but I'm sure you can read the documentation and work out what you need.

回答2:

Textout is basically a wrapper for Windows.ExtTextOut which doesn't support multiple lines. An alternative is to use DrawText:

var
  r: TRect
  s: string
begin
  s := StringReplace('a#b','#',#13#10,[rfReplaceAll]);
  r.Left := 10;
  r.Top := 10;
  DrawText(Canvas.Handle, PWideChar(s), Length(s), r, DT_NOPREFIX or DT_WORDBREAK);
end;

If you're using Delphi 7 then you will probably want to replace the PWideChar with PChar.

来源：https://stackoverflow.com/questions/10277324/delphi7-canvas-textout-cant-write-new-lines