如何在 C# 中从 Active Directory 获取用户并将其显示在 ComboBox 中

Question

I'm trying to show, in a ComboBox control, the users from an Active Directory on the network. To do this, I've the next function:

public static List<Usuario> MostrarUsuariosDominio()
    {
        List<Usuario> rst = new List<Usuario>();

        try
        {

            DirectoryContext dc = new DirectoryContext(DirectoryContextType.Domain, Environment.UserDomainName);
            Domain domain = Domain.GetDomain(dc);
            DirectoryEntry de = domain.GetDirectoryEntry();

            DirectorySearcher adSearcher = new DirectorySearcher(de); 

            adSearcher.Filter = "(&(objectClass=user)(objectCategory=person))";
            adSearcher.PropertiesToLoad.Add("samaccountname");

            SearchResult result;
            SearchResultCollection iResult = adSearcher.FindAll();

            Usuario item;
            if (iResult != null)
            {
                for (int counter = 0; counter < iResult.Count; counter++)
                {
                    result = iResult[counter];
                    if (result.Properties.Contains("samaccountname"))
                    {
                        item = new Usuario();

                        item.Nombre = (String)result.Properties["samaccountname"][0];

                        rst.Add(item);
                    }
                }
            }

            adSearcher.Dispose();
        }

        catch (Exception ex)
        {
            Usuario item = new Usuario();
            item.Nombre = "No se pudo recuperar la lista de usuarios";
            rst.Add(item);
        }

        return rst;
    }

If I run the application in the PC who's domain controller it works fine: the function returns to me all users. But if I run it on another PC, I get the exception:

Specified domain does not exist or couldn't contact with it

Is there any way to recover the users list from another PC?

Answer 1

This line:

DirectoryContext dc = new DirectoryContext(DirectoryContextType.Domain, Environment.UserDomainName);

Tells it to connect to the domain that the current user is logged into. Are you logged in as a domain user?

Maybe check what Environment.UserDomainName is equal to and see if it is right.

If it's right, then it may be a network issue - it can't talk to the domain. Do you need to be connected to VPN?

Answer 2

To get all the users in a Active Directory domain you can use an DirectorySearcher class object to querie to a domain about all the users availables in that domain.

The class DirectorySearcher is contained in System.DirectoryServices namespace and is a class to perform queries against Active Directory Domain Services.

In this page is an example about how to do it:

 ... string DomainPath = "LDAP://DC=xxxx,DC=com" DirectoryEntry searchRoot = new DirectoryEntry(DomainPath); DirectorySearcher search = new DirectorySearcher(searchRoot); search.Filter = "(&(objectClass=user)(objectCategory=person))"; search.PropertiesToLoad.Add("samaccountname"); search.PropertiesToLoad.Add("mail"); search.PropertiesToLoad.Add("usergroup"); search.PropertiesToLoad.Add("displayname");//first name SearchResultCollection resultCol = search.FindAll(); ...

In DirectorySearcher, create a DirectorySearcher object which searches for all users in a domain. search.Filter = "(&(objectClass=user)(objectCategory=person))" filters the search.

The search filter syntax looks a bit complicated, but basically it filters the search results to only include users -> "objectCategory=person" and "objectClass=user" - and excludes disabled user accounts by performing a bitwise AND of the userAccountControl flags and the "account disabled" flag.

To point to the local Active Directory domain you can use this:

DirectoryEntry searchRoot = new DirectoryEntry("WinNT://" + Environment.MachineName);

You can combine that example with this code that uses foreach instead of use the for loop in the page example:

foreach (SearchResult result in resultCol)
{
    yourComboBox.Items.Add(result.Properties["displayname"]);
}

I left here some pages from the Microsoft MSDN and codeproject.com sites:

DirectorySearcher Class

Get List of Active Directory Users in C#

SearchResultCollection Class

SearchResult Class

SearchResult.Properties Property