DSL-Verbindungsmonitor!

[Dakuba]

Das ist aus der Delphi Source Library hoffe des hilft dir:


Folgender Code stellt eine komplette Unit eines Formulars dar, die beim Klicken auf den Button feststellt, ob eineVerbindung ins Internet besteht oder nicht.

Delphi-Quellcode:

unit CheckInternetConnection1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, Registry, WinSock, WinInet;

type
  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
    private
      { Private-Deklarationen }
    public
      { Public-Deklarationen }
    end;

const
  cERROR_BUFFER_TOO_SMALL = 603;
  cRAS_MaxEntryName = 256;
  cRAS_MaxDeviceName = 128;
  cRAS_MaxDeviceType = 16;

type
  TConnectionType = (ctNone, ctProxy, ctDialup);
  ERasError = class(Exception);
    HRASConn = DWord;
    PRASConn = ^TRASConn;
    TRASConn = record
      dwSize: DWORD;
      rasConn: HRASConn;
      szEntryName: array[0..cRAS_MaxEntryName] of Char;
      szDeviceType: array[0..cRAS_MaxDeviceType] of Char;
      szDeviceName: array [0..cRAS_MaxDeviceName] of char;
    end;
    TRasEnumConnections = function (RASConn: PrasConn; var BufSize: DWord;
     var Connections: DWord): LongInt; stdcall;

var
  Form1: TForm1;

function ConnectedToInternet: TConnectionType;
function RasConnectionCount: Integer;

implementation

{$R *.DFM}

function ConnectedToInternet: TConnectionType;
var Reg: TRegistry;
  bUseProxy: Boolean;
  UseProxy: LongWord;
begin
  Result := ctNone;
  Reg := TRegistry.Create;
  with REG do
    try
      try
        RootKey := HKEY_CURRENT_USER;
        if OpenKey('Software\Microsoft\WindowsCurrentVersion\Internet settings',
        false) then begin
          if GetDataType('ProxyEnable') = rdBinary then
            ReadBinaryData('ProxyEnable', UseProxy, SizeOf(LongWord))
          else begin
            bUseProxy := ReadBool('ProxyEnable');
            if bUseProxy then UseProxy := 1
            else UseProxy := 0;
          end;
          if (UseProxy<>0) and (ReadString('ProxyServer')<>'' ) then Result := ctProxy;
        end;
      except
      end;
    finally
      Free;
    end;
    if Result = ctNone then begin
      if RasConnectionCount > 0 then Result := ctDialup;
    end;
end;

function RasConnectionCount: Integer;
var RasDLL: HInst;
  Conns: array[1..4] of TRasConn;
  RasEnums: TRasEnumConnections;
  BufSize: DWord;
  NumConns: DWord;
  RasResult: Longint;
begin
  Result := 0;
  RasDLL := LoadLibrary('rasapi32.dll');
  if RasDLL = 0 then exit;
  try
    RasEnums := GetProcAddress(RasDLL,'RasEnumConnectionsA');
    if @RasEnums = nil then
      raise ERasError.Create('RasEnumConnectionsA not found in rasapi32.dll');
    Conns[1].dwSize := Sizeof (Conns[1]);
    BufSize := SizeOf(Conns);
    RasResult := RasEnums(@Conns, BufSize, NumConns);
    if (RasResult = 0) or (Result = cERROR_BUFFER_TOO_SMALL) then Result := NumConns;
  finally
    FreeLibrary(RasDLL);
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
var Status: TConnectionType;
  sMsg: string;
begin
  Status := ConnectedToInternet;
  if Status = ctDialup then sMsg := 'Im Internet!';
  if Status = ctNone then sMsg := 'Nicht im Internet!';
  if Status = ctProxy then sMsg := 'Proxyserver';
  ShowMessage(string(sMsg));
end;

end.