See if computer exists in AD

Question

_{Friday, May 3, 2019 8:40 AM}

Hi, 

I'm fairly new to C#, I came from PowerShell which makes this task really easy.

I want to search my domain controller in a specific OU to test if a computer account exists.

In PowerShell I would have just used Get-ADComputer, in C# I'm trying to use the following code which I have found in examples online:

using (DirectoryEntry entry = new DirectoryEntry("LDAP://domain.lan/CN=company computers/DC=domain/DC=lan"))
{

    using (DirectorySearcher adsearcher = new DirectorySearcher(entry))
    {
        adsearcher.Filter = "(&(objectClass=computer) (cn=" + computerHostName + "))";
        adsearcher.SearchScope = SearchScope.Subtree;
        adsearcher.PropertiesToLoad.Add("description");
        SearchResult searchresult = adsearcher.FindOne();

         SetOutputTextbox(value: searchresult.ToString());
     }
}

But I am getting the below error:

An operations error occured, error code:

Any help is very appreciated :) 

All replies (3)

_{Friday, May 3, 2019 10:30 AM ✅Answered}

Btw, try the following:

using System.DirectoryServices;
using System.DirectoryServices.ActiveDirectory;

        public static void FindComputer(string computerHostName)
        {
            DirectoryContext dirCtx = new DirectoryContext(DirectoryContextType.Domain, "domain.lan");
            using (Domain usersDomain = Domain.GetDomain(dirCtx))
            using (DirectorySearcher adsearcher = new DirectorySearcher(usersDomain.GetDirectoryEntry()))
            {
                adsearcher.Filter = "(&(objectClass=computer) (cn=" + computerHostName + "))";
                adsearcher.SearchScope = SearchScope.Subtree;
                adsearcher.PropertiesToLoad.Add("description");
                SearchResultCollection searchResults = adsearcher.FindAll();

                foreach (SearchResult searchResult in searchResults)
                {
                    Console.WriteLine(searchResult.Properties["adspath"][0]);
                }
            }
        }

The reason why your code don't work is you need to login first. In my code it uses the default credential.

If you passes "*" as computerHostName, it should list all computer entries in the domain (it searches from "root" instead of individual OU).

_{Friday, May 3, 2019 9:53 AM}

By default, non-domain-controllers machine accounts are added to "CN=Computers" instead of "CN=Company Computers"

And I assume you know how to change the domain.lan to the actual values (not always equals to concatenation of the /DC chain values)

_{Friday, May 3, 2019 10:02 AM}

Yep, I just removed the actual names for security :)

I want to search the subtree of a certain OU (OU=Domain Computers,DC=domain,DC=lan) and see if a computer exists. 

All the examples I've seen online when searching for an object is to supply the full path which I won't know when searching.