How to know the users running the application and give message

We have shared an application from win2k server, and in need to know a way to identify the windows users currently running the application. We want to send customized messages to the users connected. How could this be done?
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David LeeCommented:
There are several possibile ways of doing this.

1.  Write a program that enumerates all the connections that have the app's exe open.
2.  Modify the app and have it create a connection list.  As users start the program they are entered in the connection list.  When they exit they are removed.
3.  Create a messenger routine in the app.  Have it check a central point periodically for new messages.  Send messages to the users by posting the message in the central point (e.g. in a database or a file located in a certain folder).
swtirsAuthor Commented:

Method you suggested fails when application crashes or when users abort running the application. Further I would like to have a source code sample that enumerates all the active connection to the exe and then send message to the workstations running the application.

David LeeCommented:
Here's the code for enumerating all the connections to a given file and sending them a message.  The message in this case is a Net Send message.  Make the changes per my comments in the code.  I tested this code in my environment (Windows 2000 AD domain, XP workstation) and it worked as advertised.

Dim colUsers as Collection

Private Sub cmdGetOpenFileUsers_Click()
    'Include a project reference to Active DS Type Library
    On Error Resume Next
    Dim objFSO As IADsFileServiceOperations, _
        objResource As IADsResource, _
        WshShell As Object, _
        strComputer As String, _
        strFilename As String, _
        strUsername As String, _
        strPath As String, _
        strMessage As String
    'Change eeBDF to the name of the computer hosting the exe
    strComputer = "eeBDF"
    'Change notepad.exe to the name of the exe you want to check on
    strFilename = "notepad.exe"
    'Change strMessage to the message you want to send to those with the file open
    strMessage = "Please exit the Notepad now."
    Set colUsers = New Collection
    Set objFSO = GetObject("WinNT://" & strComputer & "/LanmanServer")
    Set WshShell = CreateObject("WScript.Shell")
    If (IsEmpty(objFSO) = False) Then
        For Each objResource In objFSO.Resources
            objResource.GetInfoEx Array("user", "path"), 0
            strUsername = ""
            strPath = ""
            strUsername = objResource.Get("user")
            strPath = objResource.Get("path")
            If (Not strUsername = "") And (Not Right(strUsername, 1) = "$") Then
                If (InStr(1, strPath, strFilename, 1) <> 0) Then
                    colUsers.Add strUsername
                    WshShell.Run "CMD /C net send " & strUsername & " " & strMessage, 1, False
                End If
            End If
    End If
    Set objResource = Nothing
    Set objFSO = Nothing
End Sub
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if you are using ACtive Directory, it is simple to get the users name; let me know if you are and I will send you a sample of the code.

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David LeeCommented:
Normally I don't comment on a person's decision about how to close a question, but I'm going to this time.  Why would you select a comment as the best answer to your question over code that does exactly what you asked for?  
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