当文本具有三行或更多行时，我如何知道是否在 TRichEdit 中选择了所有文本？

Question

I have a TRichEdit with some RTF in it (text with formatting only) and I want to know if all the content of the TRichEdit is selected. To do so, I do:

var AllSelectd: Boolean;
//...
AllSelectd := MyRichEdit.SelLength = MyRichEdit.GetTextLen;

which works fine, except when the content has three lines or more. With zero to two lines, everything is fine. As soon as I reach three lines in my TRichEdit, the code above no longer works ( MyRichEdit.SelLength < MyRichEdit.GetTextLen ). Each line is terminated with CRLF ( #13#10 ).

Is this a bug? How can I reliably check if everything is selected in the TRichEdit?

I use Delphi 10.4, if it changes anything.

Answer 1

As mentioned in this topic , RichEdit 2.0 replaces CRLF pairs with CR internally, and retrieves LF's in some cases.

As workaround - calculate number of lines in selected range to make correction ( SelText contains only CR's, GetTextLen works with text with retrieved CRLF, so counts both CR's and LF's). Remy Lebeau proposal is used.

var
  sel, getl, crcnt, i: integer;
  tx: string;
begin
  sel := RichEdit1.SelLength;
  getl := RichEdit1.GetTextLen;
  crcnt := SendMessage(Richedit1.Handle, EM_EXLINEFROMCHAR, 0, sel);
  Memo1.Lines.Add(Format('%d %d',[sel, getl - crcnt + 1]));
end;