在使用中添加单位 WinNet。使用功能 InternetGetConnectedState返回互联网状态和类型的值。见下文：

Add in your uses the unit "WinNet". With the function "InternetGetConnectedState" return a value for internet state and type. See below:

function YourFunctionName : boolean;
  var
     origin : cardinal;
  begin
     result := InternetGetConnectedState(@origin,0);

     //connections origins by origin value
     //NO INTERNET CONNECTION              = 0;
     //INTERNET_CONNECTION_MODEM           = 1;
     //INTERNET_CONNECTION_LAN             = 2;
     //INTERNET_CONNECTION_PROXY           = 4;
     //INTERNET_CONNECTION_MODEM_BUSY      = 8;
  end;