{2. Static linking. }
uses
WinInet;
{...}
function IsConnectedToInternet: Boolean;
var
dwConnectionTypes: DWORD;
begin
dwConnectionTypes :=
INTERNET_CONNECTION_MODEM +
INTERNET_CONNECTION_LAN +
INTERNET_CONNECTION_PROXY;
Result := InternetGetConnectedState(@dwConnectionTypes, 0);
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
if IsConnectedToInternet then
ShowMessage('Connected.')
else
ShowMessage('Not Connected.')
end;
{**********************************************************}
{2. Dynamic linking. }
function IsConnectedToInternet(lpdwFlags: LPDWORD): Boolean;
const
WininetDLL = 'wininet.dll';
var
hWininetDLL: THandle;
dwReserved: DWORD;
fn_InternetGetConnectedState: function(lpdwFlags: LPDWORD; dwReserved: DWORD): BOOL; stdcall;
begin
Result := False;
dwReserved := 0;
hWininetDLL := LoadLibrary(WininetDLL);
if hWininetDLL > 0 then
begin
@fn_InternetGetConnectedState := GetProcAddress(hWininetDLL,'InternetGetConnectedState');
if Assigned(fn_InternetGetConnectedState) then
begin
Result := fn_InternetGetConnectedState(lpdwFlags, dwReserved);
end;
FreeLibrary(hWininetDLL);
end else
raise Exception.Create('Unable to locate function InternetGetConnectedState in library ' + WininetDLL);
end;
procedure TForm1.Button1Click(Sender: TObject);
const
INTERNET_CONNECTION_MODEM = 1;
INTERNET_CONNECTION_LAN = 2;
INTERNET_CONNECTION_PROXY = 4;
INTERNET_CONNECTION_MODEM_BUSY = 8;
var
dwConnectionTypes: DWORD;
begin
dwConnectionTypes :=
INTERNET_CONNECTION_MODEM +
INTERNET_CONNECTION_LAN +
INTERNET_CONNECTION_PROXY;
if IsConnectedToInternet(@dwConnectionTypes) then
ShowMessage('Connected.')
else
ShowMessage('Not Connected.')
end;
Other Possibilities/ Andere Möglichkeiten:
...determine if there is an active connection to the internet ?
...überprüfen ob eine Verbindung zum Internet besteht ?
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