Get the computer names in a network ?

[Andreas Grabher]

Hello,

I need to know, how I can get the names (or the ip-addresses) of the
different computers in a network ?
Is there a function in Delphi 3 C/S which return me these information ?

Thanks for any help,

Andreas.
an...@tmt.at
http://www.tmt.at/ante/

[Alex O.]

It gets pretty hairy but you can use the WinAPI function:

DWORD WNetEnumResource(

HANDLE hEnum, // handle to enumeration
LPDWORD lpcCount, // pointer to entries to list
LPVOID lpBuffer, // pointer to buffer for results
LPDWORD lpBufferSize // pointer to buffer size variable
);

Where:

hEnum= handle you get with the function below
lpcCount = The number of results you want, probably set as a fairly
large number.
lpBuffer = Address of array[1..lpcCount] of TNetResource
lpBufferSize = sizeof(lpBuffer)

You have to feed it the handle of an enumeration which you get using
the WinAPI function:

DWORD WNetOpenEnum(
DWORD dwScope, // scope of enumeration
DWORD dwType, // resource types to list
DWORD dwUsage, // resource usage to list
LPNETRESOURCE lpNetResource, // pointer to resource
structure
LPHANDLE lphEnum // pointer to enumeration handle buffer
);

Where:

dwScope:= RESOURCE_GLOBALNET;
dwType:= RESOURCETYPE_DISK;
dwUsage:= RESOURCEUSAGE_CONTAINER;
lpNetResource:= NIL
lphEnum is the returned THandle you put into hEnum above.

You can then iterate through the lpBuffer to get the network entries.
Since some of the entries might be workgroups, you may need to do this
recursively.

After calling WNetEnumResource, iterate through the lpBuffer entries
from which you can read the TNetResource structure entry details:

DWORD dwScope;
DWORD dwType;
DWORD dwDisplayType;
DWORD dwUsage;
LPTSTR lpLocalName;
LPTSTR lpRemoteName;
LPTSTR lpComment;
LPTSTR lpProvider;

You can then toss this structure back into the WNetOpenEnum function
above (as lpNetResource) to get a handle to toss into the
WNetEnumResource (as hEnum) and do the whole thing over to iterate
through the next level of network resource entries.

I'm new to these functions as well so if I've spewed out bogus info
somewhere, feel free to post an addendum.

- Alex Olshove

In article <89g1s1$p45$1...@apans1.apa.at>,

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[Andreas Grabher]

Hello, I got the following function from a german newsgroup.
It's very easy to use :-)

Cheers,

Andreas.

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function TMainWin.EnumClients(tar:TStrings):DWord;
var ContinueEnumeration:boolean;
Function WNetEnumeration(PNetContainer: PNetResource):DWord;
var BufferSize,NetEntries:DWORD;
i:Integer;
NetResources:TNetResources;
NetHandle:THandle;
Text:String;
begin
Result:=WNetOpenEnum(RESOURCE_GLOBALNET,RESOURCETYPE_ANY,
RESOURCEUSAGE_CONTAINER,PNetContainer,NetHandle);
if Result<>NO_ERROR then
exit;
ContinueEnumeration:=True;
while ContinueEnumeration do
begin
NetEntries:=MaxNetResources;
BufferSize:=SizeOf(NetResources);

Result:=WNetEnumResource(NetHandle,NetEntries,@NetResources[0],BufferSize);

if Result=NO_ERROR then
begin
for i:=0 to Pred(NetEntries)do
begin
if NetResources[i].dwDisplayType=RESOURCEDISPLAYTYPE_SERVER
then
begin
text:=NetResources[i].lpRemoteName;
while Pos('\',text)=1 do
Delete(text,1,1);
tar.Add(Text+' '+GetIP(Text));
end;
if NetResources[i].dwUsage<>RESOURCEUSAGE_CONNECTABLE then
WNetEnumeration(@NetResources[i]);
end;
end
else
begin
Result:=GetLastError;
ContinueEnumeration:=Result=ERROR_MORE_DATA;
end;
end;
if NetHandle<>0 then
WNetCloseEnum(NetHandle);
end;
begin
tar.Clear;
Result:=WNetEnumeration(nil);
end;

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