?
Solved

Am I connected to the Internet?

Posted on 2002-03-26
3
Medium Priority
?
154 Views
Last Modified: 2010-04-04
Using Delphi 3...

How can my D3 application detect whether the user is currently connected to the Internet or not?
0
Comment
Question by:Kapusta
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
3 Comments
 
LVL 6

Expert Comment

by:Stuart_Johnson
ID: 6897994
What type of D3 are you using?  Developer / Profession / Client Server?  Do you have any internet controls?

Stu
0
 

Author Comment

by:Kapusta
ID: 6898013
I am using Delphi Professional.  As far as components, I have the Internet Mail Suite 1.x by Artchil Gogava.
0
 
LVL 6

Accepted Solution

by:
Stuart_Johnson earned 200 total points
ID: 6898103
Hi Kapusta,

Here is some code for you.

const
  INTERNET_CONNECTION_MODEM           = 1;
  INTERNET_CONNECTION_LAN             = 2;
  INTERNET_CONNECTION_PROXY           = 4;
  INTERNET_CONNECTION_MODEM_BUSY      = 8;

function InternetGetConnectedState(lpdwFlags: LPDWORD;
  dwReserved: DWORD): BOOL; stdcall; external 'WININET.DLL';

function  _IsConnectedToInternet: Boolean;
var
  dwConnectionTypes: Integer;
begin
  try
    dwConnectionTypes := {INTERNET_CONNECTION_MODEM +}
                         INTERNET_CONNECTION_LAN +
                         INTERNET_CONNECTION_PROXY;
    if InternetGetConnectedState(@dwConnectionTypes, 0) then
      Result := true
    else
      Result := false;
  except
    Result := false;
  end;
end;



procedure TForm1.Button1Click(Sender: TObject);
begin
   if _IsConnectedToInternet then
     ShowMessage('Yes')
   else
     ShowMessage('No');
end;

This works fine, however it doesn't detect an instant disconnect/connect.  I've found I have to retry it a couple of times before it realises that you're no longer connected to the net (this is the case with Lan anyway, not sure about modem).  This is a Windows thing, not a Delphi/Code thing.

Let me know if you need anymore help,

Cheers,

Stu
0

Featured Post

Free Tool: Subnet Calculator

The subnet calculator helps you design networks by taking an IP address and network mask and returning information such as network, broadcast address, and host range.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

A lot of questions regard threads in Delphi.   One of the more specific questions is how to show progress of the thread.   Updating a progressbar from inside a thread is a mistake. A solution to this would be to send a synchronized message to the…
Introduction I have seen many questions in this Delphi topic area where queries in threads are needed or suggested. I know bumped into a similar need. This article will address some of the concepts when dealing with a multithreaded delphi database…
Do you want to know how to make a graph with Microsoft Access? First, create a query with the data for the chart. Then make a blank form and add a chart control. This video also shows how to change what data is displayed on the graph as well as form…
In this video you will find out how to export Office 365 mailboxes using the built in eDiscovery tool. Bear in mind that although this method might be useful in some cases, using PST files as Office 365 backup is troublesome in a long run (more on t…
Suggested Courses

719 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question