如何从 TRichedit 按点或按索引获取字符

Question

I have function that returns the index of a character GetCharFromPos(Pt: TPoint): Integer;

now i wanted to get character of that position. like GetCharByIndex(Index: Integer): Char;

Answer 1

The efficient way to do this using pure VCL is to use SelStart , SelLength and SelText .

function GetCharByIndex(Index: Integer): Char;
begin    
  RichEdit.SelStart := Index;
  RichEdit.SelLength := 1;
  Result := RichEdit.SelText[1];
end;

You'll likely want to save away the selection before modifying it, and then restore it once you have read the character.

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This is however a rather messy way to read a character. If you are prepared to use raw Win32 API then you can make use of EM_GETTEXTRANGE .

Answer 2

Here is how you return the character at a given index from a TRichEdit:

Result := RichEdit1.Text[Index];