Question

I am trying to use an LDAP query to return all computer objects created in the last 24 hours. My code currently looks like this:

//Declare new DirectoryEntry and DirectorySearcher
DirectoryEntry domainRoot = new DirectoryEntry("LDAP://rootDSE");
string rootOfDomain = domainRoot.Properties["rootDomainNamingContext"].Value.ToString();
DirectorySearcher dsSearch = new DirectorySearcher(rootOfDomain);

//Set the properties of the DirectorySearcher
dsSearch.Filter = "(&(objectClass=Computer)(whenCreated>" + dateFilter.ToString() + "))";
dsSearch.PageSize = 2000;
dsSearch.PropertiesToLoad.Add("distinguishedName");
dsSearch.PropertiesToLoad.Add("whenCreated");
dsSearch.PropertiesToLoad.Add("description");
dsSearch.PropertiesToLoad.Add("operatingSystem");
dsSearch.PropertiesToLoad.Add("name");

//Execute the search
SearchResultCollection computersFound = dsSearch.FindAll();

This code does not return any objects, and I know for certain that there have been accounts created in the last 24 hours.


EDIT: I fixed this with the following code:

GetCompList(DateTime.Now.AddDays(-1)); //This sets the filter to one day previous

//Declare new DirectoryEntry and DirectorySearcher
DirectoryEntry domainRoot = new DirectoryEntry("LDAP://rootDSE");
string rootOfDomain = domainRoot.Properties["rootDomainNamingContext"].Value.ToString();
DirectorySearcher dsSearch = new DirectorySearcher(rootOfDomain);

//Set the properties of the DirectorySearcher
dsSearch.Filter = "(&(objectClass=Computer)(whenCreated>=" + dateFilter.ToString("yyyyMMddHHmmss.sZ") + "))";
dsSearch.PageSize = 2000;
dsSearch.PropertiesToLoad.Add("distinguishedName");
dsSearch.PropertiesToLoad.Add("whenCreated");
dsSearch.PropertiesToLoad.Add("description");
dsSearch.PropertiesToLoad.Add("operatingSystem");
dsSearch.PropertiesToLoad.Add("name");


//Execute the search
SearchResultCollection computersFound = dsSearch.FindAll();

The secret is the line :

dsSearch.Filter = "(&(objectClass=Computer)(whenCreated>=" + dateFilter.ToString("yyyyMMddHHmmss.sZ") + "))";

Answer 1

It turns out the answer was in the formatting of the whenCreated filter. According to This blogpost, the filter for whenCreated must be formatted like “yyyyMMddHHmmss.sZ”, where Z is the offset from UTC. What I did was created a method called

private void GetCompList(DateTime dateFilter) //This overloaded version of GetCompList takes a parameter of type DateTime, and only returns computers that were built after dateFilter
    {
        try
        {
            //Convert the dateFilter to a format appropriate for an LDAP query
            int offset = -8;
            //string strDateFilter = convertToCrazyFormat(dateFilter, offset);

            //string strDateFilter = dateFilter.ToString("yyyyMMddhhmmss");

            //Declare new DirectoryEntry and DirectorySearcher
            DirectoryEntry domainRoot = new DirectoryEntry("LDAP://rootDSE");
            string rootOfDomain = domainRoot.Properties["rootDomainNamingContext"].Value.ToString();
            DirectorySearcher dsSearch = new DirectorySearcher(rootOfDomain);

            //Set the properties of the DirectorySearcher
            dsSearch.Filter = "(&(objectClass=Computer)(whenCreated>=" + dateFilter.ToString("yyyyMMddHHmmss.s" + offset.ToString()) + "))";
            dsSearch.PageSize = 2000;
            dsSearch.PropertiesToLoad.Add("distinguishedName");
            dsSearch.PropertiesToLoad.Add("whenCreated");
            dsSearch.PropertiesToLoad.Add("description");
            dsSearch.PropertiesToLoad.Add("operatingSystem");
            dsSearch.PropertiesToLoad.Add("name");

I then call the method like this:

GetCompList(DateTime.Now.AddDays(-1));//Pass in a negative value that represents the time period you want objects from, in this case the last day