deleting computer account from AD c# - c#-4.0

Question

I'm trying to delete a computer account from AD using this code:
string ldapBase = "ldap://x.y.z.com/";
string sFromWhere = ldapBase + "rootDSE";
DirectoryEntry root = new DirectoryEntry(sFromWhere, null, null, AuthenticationTypes.Secure);
string defaultNamingContext = root.Properties["defaultNamingContext"][0].ToString();
/* Retrieving the computer to remove */
sFromWhere = ldapBase + defaultNamingContext;
DirectoryEntry deBase = new DirectoryEntry(sFromWhere, null, null, AuthenticationTypes.Secure);
DirectorySearcher dsLookForDomain = new DirectorySearcher(deBase);
dsLookForDomain.Filter = "(&(cn=waprptest))"; // MACHSUPR is the computer to delete
dsLookForDomain.SearchScope = SearchScope.Subtree;
dsLookForDomain.PropertiesToLoad.Add("cn");
dsLookForDomain.PropertiesToLoad.Add("distinguishedName");
SearchResultCollection srcComputer = dsLookForDomain.FindAll();
// Deleting computer
foreach (SearchResult aComputer in srcComputer)
{
DirectoryEntry computerToDel = aComputer.GetDirectoryEntry();
computerToDel.DeleteTree();
computerToDel.CommitChanges();
}
I'm getting exception #
string defaultNamingContext = root.Properties["defaultNamingContext"][0].ToString();
as the rot.Properties count is 0
Please let me know what I'm doing wrong... I'm a newbie to AD

Answer 1

From my experience, to get the RootDSE folder, you must use this LDAP string:
LDAP://RootDSE
First of all, the LDAP must be in all capital letters, and RootDSE also has a capital R at its beginning. LDAP strings are case sensitive!
Also: if you're using .NET 3.5 or newer, you can use a PrincipalSearcher and a "query-by-example" principal to do your searching (much simpler than using DirectorySearcher!):
// create your domain context
using (PrincipalContext ctx = new PrincipalContext(ContextType.Domain))
{
// define a "query-by-example" principal - here, we search for a ComputerPrincipal
ComputerPrincipal qbeComputer = new ComputerPrincipal(ctx);
// create your principal searcher passing in the QBE principal
PrincipalSearcher srch = new PrincipalSearcher(qbeComputer);
// find all matches
foreach(var found in srch.FindAll())
{
// do whatever here - "found" is of type "Principal"
ComputerPrincipal cp = found as ComputerPrincipal;
if (cp != null)
{
// do something with the computer account
}
}
}
If you haven't already - absolutely read the MSDN article Managing Directory Security Principals in the .NET Framework 3.5 which shows nicely how to make the best use of the new features in System.DirectoryServices.AccountManagement. Or see the MSDN documentation on the System.DirectoryServices.AccountManagement namespace.