您需要执行以下操作：
向 RichEdit 发送 EM_SETEVENTMASK 消息以启用 ENM_LINK 标志。创建 RichEdit 后执行一次，然后每次 RichEdit 收到 CM_RECREATEWND 消息时再执行一次。
选择要转换为链接的所需文本。您可以使用 RichEdit 的 SelStart 和 SelLength 属性，或向 RichEdit 发送 EM_SETSEL 或 EM_EXSETSEL 消息。无论哪种方式，然后向 RichEdit 发送带有 CHARFORMAT2 结构的 EM_SETCHARFORMAT 消息，以对所选文本启用 CFE_LINK 效果。
继承 RichEdit 的 WindowProc 属性以处理 CN_NOTIFY(EN_LINK) 和 CM_RECREATEWND 消息。当收到EN_LINK 时，您可以使用ShellExecute/Ex() 启动所需的URL。
例如：
unit Unit1;
interface
uses
Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.ComCtrls;
type
TForm1 = class(TForm)
RichEdit1: TRichEdit;
Button1: TButton;
procedure FormCreate(Sender: TObject);
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
PrevRichEditWndProc: TWndMethod;
procedure InsertHyperLink(const HyperlinkText: string);
procedure SetRichEditMasks;
procedure RichEditWndProc(var Message: TMessage);
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
uses
Winapi.RichEdit, Winapi.ShellAPI;
procedure TForm1.FormCreate(Sender: TObject);
begin
PrevRichEditWndProc := RichEdit1.WindowProc;
RichEdit1.WindowProc := RichEditWndProc;
SetRichEditMasks;
RichEdit1.Text := 'Would you like to Download Now?';
RichEdit1.SelStart := 18;
RichEdit1.SelLength := 12;
InsertHyperLink('Download Now');
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
InsertHyperLink('Another Link');
end;
procedure TForm1.InsertHyperLink(const HyperlinkText: string);
var
Fmt: CHARFORMAT2;
StartPos: Integer;
begin
StartPos := RichEdit1.SelStart;
RichEdit1.SelText := HyperlinkText;
RichEdit1.SelStart := StartPos;
RichEdit1.SelLength := Length(HyperlinkText);
FillChar(Fmt, SizeOf(Fmt), 0);
Fmt.cbSize := SizeOf(Fmt);
Fmt.dwMask := CFM_LINK;
Fmt.dwEffects := CFE_LINK;
SendMessage(RichEdit1.Handle, EM_SETCHARFORMAT, SCF_SELECTION, LPARAM(@Fmt));
RichEdit1.SelStart := StartPos + Length(HyperlinkText);
RichEdit1.SelLength := 0;
end;
procedure TForm1.SetRichEditMasks;
var
Mask: DWORD;
begin
Mask := SendMessage(RichEdit1.Handle, EM_GETEVENTMASK, 0, 0);
SendMessage(RichEdit1.Handle, EM_SETEVENTMASK, 0, Mask or ENM_LINK);
SendMessage(RichEdit1.Handle, EM_AUTOURLDETECT, 1, 0);
end;
procedure TForm1.RichEditWndProc(var Message: TMessage);
type
PENLINK = ^ENLINK;
var
tr: TEXTRANGE;
str: string;
p: PENLINK;
begin
PrevRichEditWndProc(Message);
case Message.Msg of
CN_NOTIFY: begin
if TWMNotify(Message).NMHdr.code = EN_LINK then
begin
P := PENLINK(Message.LParam);
if p.msg = WM_LBUTTONUP then
begin
SetLength(str, p.chrg.cpMax - p.chrg.cpMin);
tr.chrg := p.chrg;
tr.lpstrText := PChar(str);
SendMessage(RichEdit1.Handle, EM_GETTEXTRANGE, 0, LPARAM(@tr));
if str = 'Download Now' then
begin
ShellExecute(Handle, nil, 'http://www.SomeSite.com/download', nil, nil, SW_SHOWDEFAULT);
end
else if str = 'Another Link' then
begin
// do something else
end;
end;
end;
end;
CM_RECREATEWND: begin
SetRichEditMasks;
end;
end;
end;
end.
更新：根据 MSDN：
RichEdit Friendly Name Hyperlinks
在 RichEdit 中，超链接字段实体由字符格式效果表示，这与用于构造数学对象的分隔符不同。因此，这些超链接不能嵌套，尽管在 RichEdit 5.0 和更高版本中它们可以彼此相邻。整个超链接有CFE_LINK和CFE_LINKPROTECTED的字符格式化效果，而autoURLs只有CFE_LINK属性。前者包含CFE_LINKPROTECTED，以便自动URL 扫描程序跳过友好名称链接。指令部分，即 URL，也具有 CFE_HIDDEN 属性，因为它不应该显示。 URL 本身用 ASCII 双引号括起来，前面是字符串 “HYPERLINK “。由于CFE_HIDDEN 在友好名称超链接中起着不可或缺的作用，因此不能在名称中使用。
例如，在使用 RichEdit 的写字板中，名称为 MSN 的超链接将具有纯文本
HYPERLINK “http://www.msn.com”MSN
整个链接将具有CFE_LINK 和CFE_LINKPROTECTED 字符格式属性，并且除了MSN 之外的所有链接都将具有CFE_HIDDEN 属性。
这可以在代码中轻松模拟：
procedure TForm1.FormCreate(Sender: TObject);
begin
...
RichEdit1.Text := 'Would you like to Download Now?';
RichEdit1.SelStart := 18;
RichEdit1.SelLength := 12;
InsertHyperLink('Download Now', 'http://www.SomeSite.com/downloads');
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
InsertHyperLink('A Text Link');
end;
procedure TForm1.InsertHyperLink(const HyperlinkText: string; const HyperlinkURL: string = '');
var
HyperlinkPrefix, FullHyperlink: string;
Fmt: CHARFORMAT2;
StartPos: Integer;
begin
if HyperlinkURL <> '' then
begin
HyperlinkPrefix := Format('HYPERLINK "%s"', [HyperlinkURL]);
FullHyperlink := HyperlinkPrefix + HyperlinkText;
end else begin
FullHyperlink := HyperlinkText;
end;
StartPos := RichEdit1.SelStart;
RichEdit1.SelText := FullHyperlink;
RichEdit1.SelStart := StartPos;
RichEdit1.SelLength := Length(FullHyperlink);
FillChar(Fmt, SizeOf(Fmt), 0);
Fmt.cbSize := SizeOf(Fmt);
Fmt.dwMask := CFM_LINK;
Fmt.dwEffects := CFE_LINK;
if HyperlinkURL <> '' then
begin
// per MSDN: "RichEdit doesn’t allow the CFE_LINKPROTECTED attribute to be
// set directly by programs. Maybe it will allow it someday after enough
// testing is completed to ensure that things cannot go awry"...
//
{
Fmt.dwMask := Fmt.dwMask or CFM_LINKPROTECTED;
Fmt.dwEffects := Fmt.dwEffects or CFE_LINKPROTECTED;
}
end;
SendMessage(RichEdit1.Handle, EM_SETCHARFORMAT, SCF_SELECTION, LPARAM(@Fmt));
if HyperlinkURL <> '' then
begin
RichEdit1.SelStart := StartPos;
RichEdit1.SelLength := Length(HyperlinkPrefix);
FillChar(Fmt, SizeOf(Fmt), 0);
Fmt.cbSize := SizeOf(Fmt);
Fmt.dwMask := CFM_HIDDEN;
Fmt.dwEffects := CFE_HIDDEN;
SendMessage(RichEdit1.Handle, EM_SETCHARFORMAT, SCF_SELECTION, LPARAM(@Fmt));
end;
RichEdit1.SelStart := StartPos + Length(FullHyperlink);
RichEdit1.SelLength := 0;
end;
然后通过解析点击的超链接文本在EN_LINK通知中处理：
uses
..., System.StrUtils;
...
SendMessage(RichEdit1.Handle, EM_GETTEXTRANGE, 0, LPARAM(@tr));
// Per MSDN: "The ENLINK notification structure contains a CHARRANGE with
// the start and end character positions of the actual URL (IRI, file path
// name, email address, etc.) that typically appears in a browser URL
// window. This doesn’t include the “HYPERLINK ” string nor the quotes in
// the hidden part. For the MSN link above, it identifies only the
// http://www.msn.com characters in the backing store."
//
// However, without the CFM_LINKPROTECTED flag, the CHARRANGE will report
// the positions of the entire "HYPERLINK ..." string instead, so just strip
// off what is not needed...
//
if StartsText('HYPERLINK "', str) then
begin
Delete(str, 1, 11);
Delete(str, Pos('"', str), MaxInt);
end;
if (str is a URL) then begin
ShellExecute(Handle, nil, PChar(str), nil, nil, SW_SHOWDEFAULT);
end
else begin
// do something else
end;