Delphi RichEdit根据鼠标位置定位光标的方法

本文整理自网络，侵删。

 
当RichEdit为可用状态时，是不用代码控制此操作的，TRichEdit本身就可以定位光标。但是当RichEdit开始不可用时，则此方法就可能用到了。本例中RichEdit1开始时是不可用的，当在ApplicationEvents1中接收到RichEdit1被双击时则设置RichEdit1的Enable := true;并且定位光标。
unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ComCtrls, RichEdit, AppEvnts;
 
type
  TForm1 = class(TForm)
    RichEdit1: TRichEdit;
    ApplicationEvents1: TApplicationEvents;
    procedure EnableRichEdit;
    procedure ApplicationEvents1Message(var Msg: tagMSG; var Handled: Boolean);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
  FLastMousePos: TPoint;
 
implementation
 
{$R *.dfm}
 
procedure TForm1.ApplicationEvents1Message(var Msg: tagMSG;
  var Handled: Boolean);
var
  mPos: TPoint;
begin
  if msg.message = WM_LBUTTONDBLCLK then begin
    if msg.hwnd = RichEdit1.Parent.Handle then begin
      GetCursorPos(FLastMousePos);
      EnableRichEdit;
    end;
  end ;
end;
 
procedure TForm1.EnableRichEdit;
var
  cPos: TPoint;
  retCode: integer;
  mR, mC: Word;
begin
  RichEdit1.Enabled := True;
  RichEdit1.SetFocus ;
  RichEdit1.SelStart := 0;
 
  if (FLastMousePos.X = 0) and (FLastMousePos.Y = 0) then
    GetCursorPos(FLastMousePos);
  FLastMousePos := RichEdit1.ScreenToClient(FLastMousePos);
  retCode := SendMessage(RichEdit1.Handle, EM_CHARFROMPOS, 0, LPARAM(@FLastMousePos));
  mR := HiWord(retCode);
  mC := Loword(retCode);
  cPos.X := mC ;
  cPos.Y := mR ;
  RichEdit1.CaretPos := cPos;
 
  FLastMousePos.X := 0;
  FLastMousePos.Y := 0;
end;
 
end.
 

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