Check list of users exist in Active Directory using LDAP in C#

Question

I need to pass a list of user's SamAcountName / UserPrincipalName and check if those users do exist in Active Directory.

I know that we can check only one item whether it exist or not using following method. But I need to pass a whole list of SamAcountName / UserPrincipalName and check whether users exist.

public bool UserExist(string samAccountName)
{
    try
    {
        using (var domainContext = GetPrincipalContext())
        {
            using (var foundUser = UserPrincipal.FindByIdentity(domainContext, IdentityType.SamAccountName, samAccountName))
            {
                return foundUser != null;
            }
        }
    }
    catch (Exception e)
    {
        _logger.LogWarning($"{nameof(CheckUserExistBySAM)}: Exception: {e}");
        return false;
    }
}

Answer 1

Try use something like:

UserPrincipal u = new UserPrincipal(domainContext);
PrincipalSearcher search = new PrincipalSearcher(u);
var usersInYourAD = search.FindAll();    //merge this with your list of users etc.