Question

I found How can I get a list of users from active directory?

It is helpful when I only have a few users, but I have so many users in AD, so when I run my query

if ((String)(entry.Properties["sn"].Value) == "lname"
     && (String)(entry.Properties["givenName"].Value) == "fname")
{
    return entry.Properties["samAccountName"].Value.ToString();
}

it took too long to finish.

What can I do to search one particular user logon id by first name and last name?

Answer 1

Since you’re on .NET 4, you should check out the System.DirectoryServices.AccountManagement (S.DS.AM) namespace. Read all about it here:

• Managing Directory Security Principals in the .NET Framework 3.5
• MSDN docs on System.DirectoryServices.AccountManagement

Basically, you can define a domain context and easily find users and/or groups in AD:

// set up domain context
PrincipalContext ctx = new PrincipalContext(ContextType.Domain);

// find a user - by e.g. his "samAccountName", or the Windows user name or something
UserPrincipal user = UserPrincipal.FindByIdentity(ctx, "SomeUserName");

if(user != null)
{
   // do something here....     
   string samAccountName = user.SamAccountName;
}

If you cannot find a user specified by a user name, you can also use the new search functionality:

// define a "query-by-example" principal - here, we search for a UserPrincipal 
// and with the first name (GivenName) and a last name (Surname) 
UserPrincipal qbeUser = new UserPrincipal(ctx);
qbeUser.GivenName = firstName;
qbeUser.Surname = lastName;

// create your principal searcher passing in the QBE principal    
PrincipalSearcher srch = new PrincipalSearcher(qbeUser);

// find all matches
foreach(var found in srch.FindAll())
{
    // do whatever here - "found" is of type "Principal" - it could be user, group, computer.....          
}

The new S.DS.AM makes it really easy to play around with users and groups in AD! And just finding a single user should be relatively quick, too.