Listing Network Computers

Hi guys!
I'm looking for a code that lists all computers in the LAN.
Is it possible? Is it difficult?

I'm doing the first steps in VB.

I'm using VB Studio .Net 2003. ;)
Help me. Thanks on advance

Sorry about the English but I'm a portuguese teenager.
And sorry for the ignorance! :blush:

Check this thread out. It looks like they did it.

Another
http://www.vbforums.com/showthread.p...ht=wmi+network

I'm sorry, but I can't do it.
Can anyone make a form for me please.

Sorry! I'd thank you!

I highly doubt that anyone is going to make your project for you. But if you post what you have and let us know what the problem is we will be more than happy to help you work it out.

OK! Thanx for your reply! ;)
I'll try to explain what I'm trying to do!

All I want is to make an application that sends a message to a computer in the LAN with 'net send' command.
I've already done this, but I first have to know the name or the IP of the computer I want to send the message to.

I'd like to have a listbox with all computers in the LAN (and if possible) their IPs.

So as I said what code do you have and what is the issue you're having? I know one of the links I posted has an example app attached. May not be exactly what you need but it should give you a starting point.

I've tried a 'class' file that's attached to a post. But i culdn't work witha that. Many errors.

The code that I have is very very simple:

VB Code:

Public Class Form2
    Inherits System.Windows.Forms.Form
 
#Region " Windows Form Designer generated code "
 
    Public Sub New()
        MyBase.New()
 
        'This call is required by the Windows Form Designer.
        InitializeComponent()
 
        'Add any initialization after the InitializeComponent() call
 
    End Sub
 
    'Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub
 
    'Required by the Windows Form Designer
    Private components As System.ComponentModel.IContainer
 
    'NOTE: The following procedure is required by the Windows Form Designer
    'It can be modified using the Windows Form Designer.  
    'Do not modify it using the code editor.
    Friend WithEvents Label2 As System.Windows.Forms.Label
    Friend WithEvents Label1 As System.Windows.Forms.Label
    Friend WithEvents msg_net As System.Windows.Forms.TextBox
    Friend WithEvents ip As System.Windows.Forms.TextBox
    Friend WithEvents btn_env As System.Windows.Forms.Button
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.Label2 = New System.Windows.Forms.Label
        Me.Label1 = New System.Windows.Forms.Label
        Me.btn_env = New System.Windows.Forms.Button
        Me.msg_net = New System.Windows.Forms.TextBox
        Me.ip = New System.Windows.Forms.TextBox
        Me.SuspendLayout()
        '
        'Label2
        '
        Me.Label2.BackColor = System.Drawing.Color.Transparent
        Me.Label2.ForeColor = System.Drawing.Color.Black
        Me.Label2.Location = New System.Drawing.Point(8, 32)
        Me.Label2.Name = "Label2"
        Me.Label2.Size = New System.Drawing.Size(64, 16)
        Me.Label2.TabIndex = 35
        Me.Label2.Text = "Mensagem:"
        Me.Label2.TextAlign = System.Drawing.ContentAlignment.MiddleRight
        '
        'Label1
        '
        Me.Label1.BackColor = System.Drawing.Color.Transparent
        Me.Label1.ForeColor = System.Drawing.Color.Black
        Me.Label1.Location = New System.Drawing.Point(8, 8)
        Me.Label1.Name = "Label1"
        Me.Label1.Size = New System.Drawing.Size(64, 16)
        Me.Label1.TabIndex = 34
        Me.Label1.Text = "PC / IP:"
        Me.Label1.TextAlign = System.Drawing.ContentAlignment.MiddleRight
        '
        'btn_env
        '
        Me.btn_env.BackColor = System.Drawing.Color.White
        Me.btn_env.FlatStyle = System.Windows.Forms.FlatStyle.Flat
        Me.btn_env.Location = New System.Drawing.Point(224, 8)
        Me.btn_env.Name = "btn_env"
        Me.btn_env.Size = New System.Drawing.Size(51, 88)
        Me.btn_env.TabIndex = 33
        Me.btn_env.Text = "Enviar"
        '
        'msg_net
        '
        Me.msg_net.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle
        Me.msg_net.Location = New System.Drawing.Point(80, 32)
        Me.msg_net.Multiline = True
        Me.msg_net.Name = "msg_net"
        Me.msg_net.Size = New System.Drawing.Size(139, 64)
        Me.msg_net.TabIndex = 32
        Me.msg_net.Text = ""
        '
        'ip
        '
        Me.ip.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle
        Me.ip.Location = New System.Drawing.Point(80, 8)
        Me.ip.Name = "ip"
        Me.ip.Size = New System.Drawing.Size(139, 20)
        Me.ip.TabIndex = 31
        Me.ip.Text = ""
        '
        'Form2
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(288, 110)
        Me.Controls.Add(Me.Label2)
        Me.Controls.Add(Me.Label1)
        Me.Controls.Add(Me.btn_env)
        Me.Controls.Add(Me.msg_net)
        Me.Controls.Add(Me.ip)
        Me.Name = "Form2"
        Me.Text = "Form2"
        Me.ResumeLayout(False)
 
    End Sub
 
#End Region
 
    Private Sub btn_env_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn_env.Click
        Dim ip, message
        ip = Me.ip.Text
        message = Me.msg_net.Text
        Shell("net send " & ip & message)
    End Sub
End Class

Sorry! A little change!

VB Code:

Private Sub btn_env_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn_env.Click
        Dim ip, message
        ip = Me.ip.Text
        message = Me.msg_net.Text
        Shell("net send " & ip & " " & message)
    End Sub

This is what i have!
I'm not getting any errors and the net send is working!
All I want is a list of the Network computers!

Or a list in a combobox where we select the computer we want to send the message to. :wave:

Thanks for your attention!

Check out post 3. This looks like it will work.

Can you answer my question?
According to 1st line: 'Imports System.Runtime.InteropServices'

I've to add the reference 'System.Runtime.InteropServices' to my project, right?
But I can't find it on the list.

You don't need to add a referance.
Just import System.Runtime.InteropServices.

How can i do that? :blush:

Very first line of the code:

VB Code:

Imports System.Runtime.InteropServices

OK!!! So...

And what about 'ByRef'? Why it appear underlined?
It seems not to work. :(

Post the code.

What's in red is blue underlined in VB .Net 2003:

VB Code:

Imports System.Runtime.InteropServices
 
Module Module2
 
    Structure Computer_info_101
 
        Public Platform_ID As Integer
 
        <MarshalAsAttribute(UnmanagedType.LPWStr)> Public Name As String
 
        Public Version_Major As Integer
 
        Public Version_Minor As Integer
 
        Public Type As Integer
 
        <MarshalAsAttribute(UnmanagedType.LPWStr)> Public Comment As String
 
    End Structure
 
    Declare Unicode Function NetServerEnum Lib "Netapi32.dll" ()
[COLOR=Red][B]([/B][/COLOR]ByVal Servername As Integer, ByVal level As Integer, _ByRef buffer As Integer, ByVal PrefMaxLen As Integer, _ByRef EntriesRead As Integer, ByRef TotalEntries As Integer, _ByVal ServerType As Integer, ByVal DomainName As String, _ByRef ResumeHandle As Integer) As Integer
 
    Declare Function NetApiBufferFree Lib "Netapi32.dll" ()
 
[COLOR=Red][B]([/B][/COLOR]ByVal lpBuffer As Integer) As Integer
 
    Private Const SV_TYPE_SERVER As Integer = &H2 ' All Servers
 
    Sub Main()
 
        Dim ComputerInfo As Computer_info_101
 
        Dim i, MaxLenPref, level, ret, EntriesRead, TotalEntries, ResumeHandle As Integer
 
        Dim BufPtr As Integer
 
        Dim iPtr As IntPtr
 
        MaxLenPref = -1
 
        level = 101
 
        ret = NetServerEnum(0, level, BufPtr, MaxLenPref, EntriesRead, TotalEntries, SV_TYPE_SERVER, "MSHOME", ResumeHandle) ' Replace MSHOME with your workgroup name
 
        If ret <> 0 Then
 
            Console.WriteLine("An Error has occured")
 
            Return
 
        End If
 
 
 
        ' loop thru the entries
 
        For i = 0 To EntriesRead - 1
 
            ' copy the stuff into our structure
 
            Dim ptr As IntPtr = New IntPtr([COLOR=Red][B]BufPtr[/B][/COLOR])
 
            ComputerInfo = CType(Marshal.PtrToStructure(ptr, GetType(Computer_info_101)), Computer_info_101)
 
            BufPtr = BufPtr + Len(ComputerInfo)
 
            Console.WriteLine(computerInfo.Name)
 
        Next
 
        NetApiBufferFree(BufPtr)
 
        Console.Write("Press Enter to End")
 
        Dim s As String = Console.ReadLine()
 
    End Sub
End Module

Why is this hapening?? Can you explain? :confused:

OK! I changed the code and now it's all right!

Here's the code:

VB Code:

Imports System.Runtime.InteropServices
 
Module Module2
 
    Structure Computer_info_101
        Public Platform_ID As Integer
        <MarshalAsAttribute(UnmanagedType.LPWStr)> Public Name As String
        Public Version_Major As Integer
        Public Version_Minor As Integer
        Public Type As Integer
        <MarshalAsAttribute(UnmanagedType.LPWStr)> Public Comment As String
 
    End Structure
 
    Declare Unicode Function NetServerEnum Lib "Netapi32.dll" (ByVal Servername As Integer, ByVal level As Integer, ByRef buffer As Integer, ByVal PrefMaxLen As Integer, ByRef EntriesRead As Integer, ByRef TotalEntries As Integer, ByVal ServerType As Integer, ByVal DomainName As String, ByRef ResumeHandle As Integer) As Integer
    Declare Function NetApiBufferFree Lib "Netapi32.dll" (ByVal lpBuffer As Integer) As Integer
    Private Const SV_TYPE_SERVER As Integer = &H2 ' All Servers
 
    Sub Main()
 
        Dim ComputerInfo As Computer_info_101
        Dim i, MaxLenPref, level, ret, EntriesRead, TotalEntries, ResumeHandle As Integer
        Dim BufPtr As Integer
        Dim iPtr As IntPtr
 
        MaxLenPref = -1
 
        level = 101
 
        ret = NetServerEnum(0, level, BufPtr, MaxLenPref, EntriesRead, TotalEntries, SV_TYPE_SERVER, "MSHOME", ResumeHandle) ' Replace MSHOME with your workgroup name
 
        If ret <> 0 Then
 
            Console.WriteLine("An Error has occured")
 
            Return
 
        End If
 
        ' loop thru the entries
 
        For i = 0 To EntriesRead - 1
 
            ' copy the stuff into our structure
 
            Dim ptr As IntPtr = New IntPtr(BufPtr)
 
            ComputerInfo = CType(Marshal.PtrToStructure(ptr, GetType(Computer_info_101)), Computer_info_101)
 
            BufPtr = BufPtr + Len(ComputerInfo)
 
            Console.WriteLine(ComputerInfo.Name)
 
        Next
 
        NetApiBufferFree(BufPtr)
 
        Console.Write("Press Enter to End")
 
        Dim s As String = Console.ReadLine()
 
    End Sub
End Module

Sorry about the ignorance! :blush:

And now? How can I use the module? How can I apply it to a ListBox??? :confused:

You'll want to change it to a function instead of a sub. And you don't want the name to be main, change it to something meaningful. And you are changing it to a function to return a value, in your case you will probably want a string array. Then instead of writing to the console you will insert it into the array, and return that array.

Quote:

---

Originally Posted by mpdeglau

You'll want to change it to a function instead of a sub. And you don't want the name to be main, change it to something meaningful. And you are changing it to a function to return a value, in your case you will probably want a string array. Then instead of writing to the console you will insert it into the array, and return that array.

---

Can you tell me how to do it? :blush:
I'm not an expert on VB .Net!!!! :D

Thanks for all! I've been learning many things with you!
;) Microbyte! :wave: