请高手解答-网络问题.

Question

在idTCPServer控件如何检测到Ｃlient的非正常断开．或者在IdTCPClient如何检测到连接的非正常断开．还有ＴServerSocket和TClientSocket

Answer 1

client端判断是否连网：
procedure TForm1.Button1Click(Sender: TObject);
begin
  if GetSystemMetrics(SM_NETWORK) AND $01 = $01 then
    ShowMessage('Machine is attached to network') else
    ShowMessage('Machine is not attached to network');
end;

Answer 2

procedure TForm1.ServerSocket1ClientDisconnect(Sender: TObject;
  Socket: TCustomWinSocket);
var
  i,j:integer;
  s:string;
begin
  j:=0;
  for i:=1 to clientcount do
  begin
     if clientsocket[i]=socket then
       j:=i;
  end;   if j=0 then
   begin
     application.MessageBox('通信出错9!','出错!',mB_OK);
     exit;
   end;   listbox1.Items.Delete(j-1);   s:=clientsocket[j].remoteaddress+'-'+clientuser[j]+'已经离开!';   for i:=j to clientcount-1 do
   begin
     clientsocket[i]:=clientsocket[i+1];
     clientuser[i]:=clientuser[i+1];
   end;   clientcount:=clientcount-1;
   edit1.Text:=inttostr(clientcount);
   memo1.Lines.Add(s);   for i:=1 to clientcount do
   begin
   clientsocket[i].SendText(s);
     end;
end;