procedure TForm1.Button3Click(Sender: TObject);

var

  pf: PARAFORMAT2;

begin

  FillChar(pf, sizeof(paraformat2), #0);

  pf.cbSize := SizeOf(paraformat2);

  pf.dwMask := PFM_LINESPACING  ;   //需要设置上 PFM_LINESPACING 标志，bLineSpacingRule和dyLineSpacing才可能有效

//  pf.bLineSpacingRule := 0;   //单倍行距，dyLineSpacing的值将被忽略

//  pf.bLineSpacingRule := 1;   //1.5倍行距，dyLineSpacing的值将被忽略

//  pf.bLineSpacingRule := 2;   //两倍行距，dyLineSpacing的值将被忽略

//  pf.bLineSpacingRule := 3;   //用dyLineSpacing以缇为单位指定行间距，当此值小于单倍行距时，效果为单倍行距

//  pf.bLineSpacingRule := 5;   //用dyLineSpacing/20指定行间距

  pf.bLineSpacingRule := 4;   //用dyLineSpacing以缇为单位指定行间距

  pf.dyLineSpacing := RichEdit1.Font.Size * 20 + 20 * 4; //这是笔者大概计算的，可以根据字体大小调节的，行间最小距离，大字体时可能出现上下行重叠，可以设置为300或者自己计算

  RichEdit1.SelectAll;   //只对选择的文本有效，***重要***

  SendMessage(RichEdit1.Handle, EM_SETPARAFORMAT, 0, LPARAM(@pf));

  RichEdit1.SelStart := 0;

  RichEdit1.SelLength := 0;

end;

procedure TForm1.Button4Click(Sender: TObject);

const

  PFNS_PAREN = $000;  //e.g. 1)

  PFNS_PARENS = $100;  //e.g. (1)

  PFNS_PERIOD = $200;  //e.g. 1.

  PFNS_PLAIN = $300;

  PFNS_NONUMBER = $400;

const

  PFN_NONE     = $00000000;  //无

  PFN_BULLET   = $00000001;  //黑色实心圆点

  PFN_ARABIC   = $00000002;  //0,1,2

  PFN_LCLETTER = $00000003;  //a,b,c

  PFN_UCLETTER = $00000004;  //A,B,C

  PFN_LCROMAN  = $00000005;  //i,ii,iii

  PFN_UCROMAN  = $00000006;  //I,II,III

  var

  pf: PARAFORMAT2;

begin

  FillChar(pf, sizeof(paraformat2), #0);

  pf.cbSize := SizeOf(paraformat2);

  //PFM_NUMBERING: wNumbering 值有效

  //PFM_NUMBERINGSTYLE: wNumberingStyle值有效

  //PFM_NUMBERINGSTART: wNumberingStart值有效

  //PFM_STARTINDENT: dxStartIndent值有效

  pf.dwMask := PFM_NUMBERING or PFM_NUMBERINGSTYLE or PFM_NUMBERINGSTART or PFM_STARTINDENT;//or PFM_OFFSET;

  pf.wNumberingStyle := PFNS_PERIOD;  //设置行号的样式，可以为“)”，“.”，“()”

  pf.wNumberingStart := 1;            //设置行号起始值

  pf.wNumbering := PFN_ARABIC;        //设置行号的格式，可以为阿拉伯数字或者英文字母等格式

  pf.dxStartIndent := 60;             //设置行首缩进值

  RichEdit1.SelectAll;

  SendMessage(RichEdit1.Handle, EM_SETPARAFORMAT, 0, LPARAM(@pf));

  RichEdit1.SelStart := 0;

  RichEdit1.SelLength := 0;

end;

3. 根据鼠标位置定位光标的方法。

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.

unit Unit1;

interface

uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, StdCtrls, ComCtrls, RichEdit, ShellAPI;

type

  TForm1 = class(TForm)

    RichEdit1: TRichEdit;

    procedure FormCreate(Sender: TObject);

  private

    { Private declarations }

  public

    procedure WndProc(var Msg: TMessage); override;

  end;

var

  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);

var

  mask: Word;

begin

  mask := SendMessage(RichEdit1.Handle, EM_GETEVENTMASK, 0, 0);

  SendMessage(RichEdit1.Handle, EM_SETEVENTMASK, 0, mask or ENM_LINK);

  SendMessage(RichEdit1.Handle, EM_AUTOURLDETECT, Integer(True), 0);

end;

procedure TForm1.WndProc(var Msg: TMessage);

var

  p: TENLink;

  sURL: string;

  CE : TRichEdit;

begin

  if (Msg.Msg = WM_NOTIFY) then

  begin

    if (PNMHDR(Msg.lParam).code = EN_LINK) then

    begin

      p := TENLink(Pointer(TWMNotify(Msg).NMHdr)^);

      if (p.Msg = WM_LBUTTONDOWN) then

      begin

        try

          CE := tRichEdit(Self.ActiveControl);

          SendMessage(CE.Handle, EM_EXSETSEL, 0, Longint(@(p.chrg)));

          sURL := CE.SelText;

          ShellExecute(0, 'open', PChar(sURL), 0, 0, SW_SHOWNORMAL);

        except

        end;

      end;

    end;

  end;

  inherited;

end;

end.