前一阵因为工作需要写了一个类来进行windows拨号，整理了一下，多封装了几个windows ras api，放上来大家提提意见。现在支持读取windows拨号连接列表、拨号、挂断、创建/删除连接，可以适用98/2000/XP，windows me 和NT没测试过，想来应该是可以的。以后有时间写成component，加入对拨号事件的支持。

uses
  ras, Classes, SysUtils, StrUtils, Windows, Forms;

type
  ERasError = Exception;

type
  TRASConnection = class
  private
    FPlatForm: integer;
    FConnected: Boolean;
    FRasEntries: TStringList;
    FRasConn: HRASCONN;
    FParams: RasDialParams;
    Ferrno: integer;
    function GetPassword: string;
    procedure SetPassword(Password: string);
    function GetPhoneNo: string;
    procedure SetPhoneNo(Number: string);
    function GetCallBack: string;
    procedure SetCallBack(Number: string);
    function GetDomain: string;
    procedure SetDomain(Domain: string);
    function GetUserName: string;
    procedure SetUserName(UserName: string);
    function GetEntryName: string;
    procedure SetEntryName(Entry: string);
    function GetConnected: Boolean;
    procedure SetConnected(AValue: Boolean);
    function GetRasEntries: TStringList;
  public
    property RasEntries: TStringList read GetRasEntries;
    property PhoneNumber: string read GetPhoneNo write SetPhoneNo;
    property CallBackNumber: string read GetCallBack write SetCallBack;
    property Domain: string read GetDomain write SetDomain;
    property EntryName: string read GetEntryName write SetEntryName;
    property username: string read GetUsername write SetUsername;
    property password: string read GetPassword write SetPassword;
    property Active: Boolean read GetConnected write SetConnected;
    procedure Connect;
    procedure DisConnect;
    function GetErrorCode: integer;
    procedure FreeAndHangup;
    constructor Create; reintroduce;
    destructor Destroy; override;
    procedure CreateRasEntry;
    procedure DeleteRasEntry(AEntryName: string);
      //function GetErrorReason: integer;
  end;

implementation

{ TRASConnection }

procedure TRASConnection.Connect;
var
  i: integer;
  s: string;
begin
  FParams.dwSize := sizeof(RasDialParams);
  i := RasDial(nil, nil, @FParams, 0, nil, @FRasConn);
  if i <> 0 then begin
    Ferrno := i;
    case i of
      691: s := ''''身分验证失败!'''';
      692: s := ''''打开端口失败!'''';
      676: s := ''''线路忙,请稍候再拨!'''';
      677: s := ''''语音响应错误!'''';
      678: s := ''''没有应答!'''';
      679: s := ''''无载波信号!'''';
      680: s := ''''无拨号音!'''';
    else
      s := ''''未知错误!'''';
    end;
    RasHangUp(FRasConn);
    raise ERasError.Create(s);
  end
  else FConnected := True;
end;

procedure TRASConnection.DisConnect;
begin
  RasHangup(FRasConn);
  FRasConn := 0;
end;

function TRASConnection.GetCallBack: string;
begin
  Result := string(FParams.szCallbackNumber);
end;

function TRASConnection.GetConnected: Boolean;
var
  i, len, num: integer;
  x: array of RASCONN;
begin
  Result := False;
  SetLength(x, 1);
  x[0].dwSize := sizeof(RASCONN);
  len := x[0].dwSize;
  num := 0;
  RasEnumConnections(@x[0], @len, @num);
  if num > 0 then begin
    SetLength(x, num);
    x[0].dwSize := sizeof(RASCONN);
    len := x[0].dwSize; num := 0;
    RasEnumConnections(@x[0], @len, @num);
    for i := 1 to num do
      if StrComp(x[i - 1].szEntryName, PChar(EntryName)) = 0 then begin
        FRasConn := x[i - 1].hrasconn;
        Result := True;
        Break;
      end;
  end;
  SetLength(x, 0);
end;

function TRASConnection.GetDomain: string;
begin
  Result := string(FParams.szDomain);
end;

function TRASConnection.GetErrorCode: integer;
begin
  Result := FErrno;
end;

function TRASConnection.GetPassword: string;
begin
  Result := ''''**********'''';
end;

function TRASConnection.GetPhoneNo: string;
begin
  Result := string(FParams.szPhoneNumber);
end;

function TRASConnection.GetEntryName: string;
begin
  Result := string(FParams.szEntryName);
end;

function TRASConnection.GetUserName: string;
begin
  Result := string(FParams.szUserName);
end;

procedure TRASConnection.SetCallBack(Number: string);
begin
  StrLCopy(FParams.szCallbackNumber, PChar(Number), sizeof(FParams.szCallbackNumber) - 1);
end;

procedure TRASConnection.SetConnected(AValue: Boolean);
begin
  if AValue and not GetConnected then Connect
  else if not AValue and GetConnected then DisConnect;
end;

procedure TRASConnection.SetDomain(Domain: string);
begin
  StrLCopy(FParams.szDomain, PChar(Domain), sizeof(FParams.szDomain) - 1);
end;

procedure TRASConnection.SetPassword(Password: string);
begin
  StrLCopy(FParams.szPassword, PChar(Password), sizeof(FParams.szPassword) - 1);
end;

procedure TRASConnection.SetPhoneNo(Number: string);
begin
  StrLCopy(FParams.szPhoneNumber, PChar(Number), sizeof(FParams.szPhoneNumber) - 1);
end;

procedure TRASConnection.SetEntryName(Entry: string);
var
  i: integer;
begin
  for i := 0 to FRasEntries.Count - 1 do
    if FRasEntries.Strings[i] = Entry then begin
      StrCopy(FParams.szEntryName, PChar(Entry));
      Exit;
    end;
  StrCopy(FParams.szEntryName, '''''''');
end;

procedure TRASConnection.SetUserName(UserName: string);
begin
  StrLCopy(FParams.szUserName, PChar(UserName), sizeof(FPArams.szUserName) - 1);
end;

procedure TRASConnection.FreeAndHangup;
begin
  if Active then DisConnect;
  Free;
end;

function TRASConnection.GetRasEntries: TStringList;
var
  ren: array of RASEntryName;
  ren98: array of RASEntryName98;
  c, l: integer;
begin
  FRasEntries.Clear;
  c := 0;
  case FPlatForm of
  VER_PLATFORM_WIN32_WINDOWS:
    begin
      setlength(ren98, 1);
      ren98[0].dwSize := sizeof(RASENTRYNAME98);
      l := sizeof(RASENTRYNAME98);
      if RasEnumEntries(nil, nil, @ren98[0], @l, @c) = ERROR_BUFFER_TOO_SMALL then begin
        setlength(ren, c);
        RasEnumEntries(nil, nil, @ren98[0], @l, @c);
      end;
      while c > 0 do begin
        FRasEntries.Add(string(ren98[c - 1].szEntryName));
        Dec(c);
      end;
      SetLength(ren98, 0);
    end;
  VER_PLATFORM_WIN32_NT:
    begin
      setlength(ren, 1);
      ren[0].dwSize := sizeof(RASENTRYNAME);
      l := sizeof(RASENTRYNAME);
      if RasEnumEntries(nil, nil, @ren[0], @l, @c) = ERROR_BUFFER_TOO_SMALL then begin
        setlength(ren, c);
        RasEnumEntries(nil, nil, @ren[0], @l, @c);
      end;
      while c > 0 do begin
        FRasEntries.Add(string(ren[c - 1].szEntryName));
        Dec(c);
      end;
      SetLength(ren, 0);
    end;
  end;
  if FRasEntries.Count>0 then EntryName:=FRasEntries.Strings[0];
  Result := FRasEntries;
end;

constructor TRASConnection.Create;
var
  OS: OSVersionInfoA;
begin
  inherited;
  OS.dwOSVersionInfoSize:=sizeof(OSVersionInfoA);
  GetVersionEx(OS);
  FPlatForm:=OS.dwPlatformId;
  FRasEntries := TStringList.Create;
  GetRasEntries;
end;

destructor TRASConnection.Destroy;
begin
  FRasEntries.Free;
  inherited;
end;

procedure TRASConnection.CreateRasEntry;
begin
  RasCreatePhonebookEntry(Application.Handle,nil);
end;

procedure TRASConnection.DeleteRasEntry(AEntryName: string);
var
  i: integer;
begin
  i:=FRasEntries.IndexOf(AEntryName);
  if i=-1 then Exit;
  FRasEntries.Delete(i);
  if AEntryName=EntryName then
    if FRasEntries.Count>0 then EntryName:=FRasEntries.Strings[0]
    else EntryName:='''''''';
  RasDeleteEntry(nil,PChar(AEntryName));
end;

Api声明：

function RasDial(
  lpRasDialExtensions: PRASDIALEXTENSIONS;
  lpszPhonebook: LPCTSTR;
  lpRasDialParams: LPRASDIALPARAMS;
  dwNotifierType: DWORD;
  lpvNotifier: Pointer;
  lphRasConn: LPHRASCONN): DWORD;
stdcall; external ''''RASAPI32.dll'''' name ''''RasDialA'''';

function RasHangUp(rasconn: HRASCONN): DWORD;
stdcall; external ''''RASAPI32.dll'''' name ''''RasHangUpA'''';

function RasGetEntryDialParams(
  lpszPhonebook: LPCTSTR;
  lprasdialparams: LPRASDIALPARAMS;
  lpfPassword: LPBOOL): DWORD;
stdcall; external ''''RASAPI32.dll'''' name ''''RasGetEntryDialParamsA'''';

function RasEnumEntries(
  reserved: LPCTSTR;
  lpszPhonebook: LPCTSTR;
  lprasentryname: LPRASENTRYNAME;
  lpcb: LPDWORD;
  lpcEntries: LPDWORD): DWORD;
stdcall; external ''''RASAPI32.dll'''' name ''''RasEnumEntriesA'''';

function RasEditPhonebookEntry(
  hwnd: HWND;
  lpszPhonebook: LPCTSTR;
  lpszEntryName: LPCTSTR): DWORD;
stdcall; external ''''RASAPI32.dll'''' name ''''RasEditPhonebookEntryA'''';

function RasGetEntryProperties(
  lpszPhonebook: LPCTSTR;
  lpszEntry: LPCTSTR;
  lpRasEntry: LPRASENTRY;
  lpdwEntryInfoSize: LPDWORD;
  lpbDeviceInfo: PBYTE;
  lpdwDeviceInfoSize: LPDWORD): DWORD;
stdcall; external ''''RASAPI32.dll'''' name ''''RasGetEntryPropertiesA'''';

function RasSetEntryProperties(
  lpszPhonebook: LPCTSTR;
  lpszEntry: LPCTSTR;
  lpRasEntry: LPRASENTRY;
  dwEntryInfoSize: DWORD;
  lpbDeviceInfo: PByte;
  dwDeviceInfoSize: DWORD): DWORD;
stdcall; external ''''RASAPI32.dll'''' name ''''RasSetEntryPropertiesA'''';

function RasEnumConnections(
  lprasconn: LPRASCONN;
  lpcb: LPDWORD;
  lpcConnections: LPDWORD): DWORD;
stdcall; external ''''RASAPI32.dll'''' name ''''RasEnumConnectionsA'''';

function RasEnumDevices(
  lpRasDevInfo: LpRasDevInfo;
  lpcb: LPDWORD;
  lpcdevices: LPDWORD): DWORD;
stdcall; external ''''RASAPI32.dll'''' name ''''RasEnumDevicesA'''';

function RasCreatePhonebookEntry(
  Handle: Hwnd; LpszPhoneBook: PChar): DWORD;
stdcall; external ''''RASAPI32.dll'''' name ''''RasCreatePhonebookEntryA'''';

function RasDeleteEntry(
  lpszPhonebook: PChar;
  lpszEntry: PChar): DWORD;
stdcall; external ''''RASAPI32.dll'''' name ''''RasDeleteEntryA'''';