vb.net - An unhandled exception of type 'System.Net.Sockets.SocketException' LAN network -

i made treeview show users on lan network , work.

• when click on user show ip , pcname without problem, but
• when click on main network "homegroup" message below

an unhandled exception of type 'system.net.sockets.socketexception' occurred in system.dll

and highlight line:

with system.net.dns.gethostbyname(compname)

function getipaddress(byval compname string) string     dim oaddr system.net.ipaddress     dim saddr string     try         system.net.dns.gethostbyname(compname)             oaddr = new system.net.ipaddress(.addresslist(0).address)             saddr = oaddr.tostring         end         getipaddress = saddr         end try  end function 

update

 function getipaddress(byval compname string) string     dim oaddr system.net.ipaddress     dim saddr string     try     catch ex exception         system.net.dns.gethostbyname(compname)             end             oaddr = new system.net.ipaddress(.addresslist(0).address)             saddr = oaddr.tostring         end         getipaddress = saddr         end try end function 

here example in vb.net forms application.

i have added comments in code if have more questions, feel free ask:

public class form4      private sub form4_load(sender object, e eventargs) handles mybase.load         'an array of predefined users, testing purposes.          'you can use lan users instead.         dim usr_array() string = {"user1", "user2", "user3"}          'first add homegroup node, can add yours.         dim mainnode new treenode()         'name of node hold node type, group in case         mainnode.name = "group"         mainnode.text = "homegroup"         me.treeview1.nodes.add(mainnode)          'loop through user list , add them         each usr in usr_array             dim usrnode new treenode()             'the name of nodes user represent             'the type of nodes             usrnode.name = "user"             usrnode.text = usr             mainnode.nodes.add(usrnode)         next usr     end sub     private sub treeview1_afterselect(sender object, e treevieweventargs) handles treeview1.afterselect         'after select, check if performed mouse click         if e.action = treeviewaction.bymouse             select case e.node.name                 case "group"                     msgbox("group node clicked")                 case "user"                     msgbox("user node clicked")                     'call getipaddress function here             end select         end if     end sub end class