There are two ways to remove an entry. The first way is to search for a node an remove it, along with all of its children. The second way is to search for a node and remove one or more of its children. Below I will demonstrate both methods.

Dim dir As New LdapConnection(MySettings)

Using users As DirectoryEntry = dir.GetObject(MyQuery)
    For Each r As DirectoryEntry In users.Children
        users.Children.Remove(r)
    Next
    users.CommitChanges()
End Using

Above shows us searching for a node then looping through each child and removing it. We could also examine the properties and delete based on that.

If you want to delete a specific item its easier and more efficient to use the following method

Using users As DirectoryEntry = dir.GetObject(MyUserQuery)
    users.DeleteTree()
    users.CommitChanges()
End Using

In the above example we just search directly for a single node (user) then call the ‘DeleteTree’ method. It the entry we searched for had any children, they would also be deleted.

I hope this helps you out. Don’t forget to leave comments if this helped, or you need any more info, thanks.

When your on the screen you want to capture just hold down the ‘Home’ key and press the ‘Sleep’ button. The screen will flash and the screen shot will now be in your pictures folder. The screen shots are stored in PNG format and can be transferred to a PC or Mac. This even works on the iPod touch. Once you have taken a screen shot the next time you plug the iPod into the computer you will see the iPod as a drive in your system. The pictures can then just be drag and dropped.

Simple Directory Search

To perform a simple query you can use the following syntax:

Dim results as SearchResultCollection

Using dir As New DirectoryEntry(connectionPath, principle, credentials, AuthenticationTypes.ServerBind)
	Dim s As New DirectorySearcher
	s.SearchRoot = dir
        s.Filter = (&(objectClass=groupOfUniqueNames)(cn=techSupport))
        s.SearchScope = SearchScope.Subtree
        results = s.FindAll
End Using

1. First we are declaring a variable to hold our search results.
2. Next we open up a connection to the LDAP directory. This is done by instantiating a DirectoryEntry object. The DirectoryEntry object requires the connection path in the form of a URL (LDAP://MyServer:10389/OU=subdir,O=parent”), the principle (”uid=myuser,ou=system”), credentials (”mypassword”), and the method of authentication (this will depend upon your LDAP directory).
3. In order to search the directory we need to use the DirectorySearcher Object. We assign our DirectoryEntry object to the SearchRoot property, this will tell the DirectorySearcher where to base its search. The Filter property needs the details of what we are searching for, in this example we are looking for an entry whose ObjectClass is “groupOfUniqueNames” and CN is “techSupport”. The ampersand in front of the query tells the searcher this is an AND operation. The SearchScope property tells the searcher that we want to search the whole sub tree from the SearchRoot down.
4. Lastly we return the results.

This is a very basic example of searching the directory. The directory is searchable on any property that an object may have, e.g. you may want to find all entries whose are inetOrgPerson and have a surname of smith. In that example your filter would be

(&(objectClass=inetOrgPerson)(sn=Smith))

Performing An Update

You can perform an update on a directory entry just like you can in a database. When performing an update it is important to remember an entry can have multiple properties of the same name. In other words the properties are in fact arrays. The following is an example of an update.

Public Sub UpdateUser(ByVal username as String, ByVal firstName as String, ByVal surname as String)

        Dim myUserDN As String = String.Format("{0}uid={1},{2}", _settings.LDAPUrl, username, _settings.UsersDN)
	Using u As New DirectoryEntry(myUserDN, _settings.Principle, _settings.Credentials, AuthenticationTypes.ServerBind)
	    AddUpdateProperty(u, "cn", firstName)
            AddUpdateProperty(u, "sn", surname)
 	    u.CommitChanges()
	End Using
End Sub

Private Sub AddUpdateProperty(ByVal r As DirectoryEntry, ByVal propName As String, ByVal value As Object)
        If r.Properties(propName).Count = 0 Then
            r.Properties(propName).Add(value)
        Else
            r.Properties(propName).Item(0) = value
	End If
End Sub

The above code shows two sub routines. Lets look at the first one, UpdateUser:

1. First we construct the URL to the object we want. We supply the LDAP URL along with the path to the entry we want.
2. Next we attempt to connect straight to our entry using the DirectoryEntry object. If the object is not found this line will throw a DirectoryServicesCOMException exception.
3. Now we can go ahead and update the properties we need to change. This is done via a helper function to handle the fact the entry could contain none, one or many of the property.
4. Lastly we call the CommitChanges method on the Directory Entry.

Performing An Insert

Performing an insert on the directory is very similar to performing an update. The code below shows how we can insert a new user type entry.

Using users As New DirectoryEntry(userDNRoot, _settings.Principle, _settings.Credentials, AuthenticationTypes.ServerBind)
    Using newUser As DirectoryEntry = users.Children.Add(String.Format("uid={0}", username), "person")

        ' add user required properties
        AddUpdateProperty(newUser, "cn", forename)
        AddUpdateProperty(newUser, "sn", surname)
        newUser.CommitChanges()
    End Using
End Using

Lets look at the code:

1. We need to connect to the LDAP directory. This time we connect to the root DN of where we want to add our new entry. Think of this as XML, we are going to add a child entry to the root.
2. Once we have a connection, we can use the Children.Add methods to create a new DirectoryEntry object. As a parameter we pass in the name of the entry.
3. Using the same helper function we saw above in the update functionality we create the properties on the object (note that this is a shortened list).
4. Once we have assigned all the properties we go ahead and commit changes.

You can download this sample project to check out some working examples.

If you have found the above article useful, have any comments or questions on it please leave a comment, and if you are a Digg user, don’t forget to give it a Digg, thanks.

I have submitted it the Windows Live Gallery, but I have no idea how long the submission process takes.

My Plugin and its details can be found here.

Tags: WLW Amazon

Designs Advice

The Internet to the rescue. It seems the guy over here came back from a trip to find he had been burgled. Due to some sniffing around, the Internet, Digg, and a stupid kid he managed to get most of his stuff back. Its worth a read!

I use this feature a lot but recently I came across a couple of videos that would play fine in WMP but when played on the Xbox would be audio with no picture. I thought this was a limitation on the part of the way the Xbox does its decoding.

After a bit of digging around the web I re-read the December 2007 Xbox 360 video playback FAQ and discovered that this is a problem with PAL and VGA playback on the Xbox. The good news is that there is a fix, and it actually works. Check out the article:

40. When trying to play 25 or 50 fps content, I don’t get any video over VGA

on the FAQ for details on the fix.

Tags: Xbox 360 VGA DivX

After I signed up for my free account at recaptcha.net I read about how it works.

Each new word that cannot be read correctly by OCR is given to a user in conjunction with another word for which the answer is already known. The user is then asked to read both words. If they solve the one for which the answer is known, the system assumes their answer is correct for the new one. The system then gives the new image to a number of other people to determine, with higher confidence, whether the original answer was correct.

You can read more about it here.

Tags: reCAPTCHA