How to know if my DirectoryEntry is really connected to my LDAP directory?

Question

I'm connecting to a LDAP directory in C#, so I've used the DirectoryEntry class.

When you do the "new DirectoryEntry" with address, login, and password it is supposed to connect to the LDAP directory.

However, even if the connection didn't work, it returns without problem, and the directoryentry variable is set.

So i do i know my connection is really opened ? Right now, I'm using a very very ugly hack : i put a "if(mydirectory.SchemaEntry)" which generates an exception if the connection wasn't etablished, because some of the members of the DirectoryEntry, such as SchemaEntry, aren't set if the connection failed. But 1:that's gotta be 11/10 on the ugliness scale 2:that takes a lot of time before failing.

So what is the good way to do this ? Surely, Microsoft must have provided something (even if I'm using a LDAP directory and not an Active Directory) to know if I'm really connected ?

Solution 1

Ok so marc_s's solution was approximately what i was doing (except i was looking for SchemaEntry and not NativeObject). But the timeout delay is much too long (the query is run to fill autocompletion values for a form). I think I actually prefer to pretend the connection is open and let the query run. That way, i can set my own, smaller, timeout delay.

Solution 2

Just "newing" up a DirectoryEntry does NOT create a connection to the LDAP store.

Only once you start using its properties, or when you access the .NativeObject property explicitly, you'll actually get a connection to the LDAP store.

In order to make sure you're connected, just read out the (DirectoryEntry).NativeObject in a try...catch clause - if it bombs out, you have a problem, otherwise your connection is now up and active.

Unfortunately, to my knowledge, there is no property or method you can call to figure out whether or not you've successfully connected to LDAP using DirectoryEntry.

Marc

Solution 3

You can check DirectoryEntry.Properties.Count. If it's > 0, it's a valid object. .Properties is never null - you'll be able to read the count even if you're not connected up to a valid DirectoryEntry, and a valid DE will always have at least one property.

No try/catch or exceptions necessary.

Solution 4

You can check DirectoryEntry.Properties.Count. If it's > 0,for a valid object. But still let say your LDAP server is down. you can't identify it with any of its properties.Instead you can catch it using the try catch block

try         
{    
     entry = new DirectoryEntry("priorityLDAPServer", sUserName, sPassword, AuthenticationTypes.None);      
   if(entry.Properties.Count > 0) 
   {               
        object o = entry.NativeObject;        
     `   next need to check user record in application database`      
   }
 }        
    catch (System.Runtime.InteropServices.COMException comex)       
{    

 //throws you the error if LDAP   server is down or wrong "Server is invalid "          
 //  you can further do a nested try catch within this block if you to try a     optional LDAP server.*
}       

Hope this helps you

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Comments

[JonBrave]

Unfortunately not true (tested under .NET 4, in 2015); which is a shame for me, as I am looking for non-exception test. While DirectoryEntry.Properties in itself is non-null, even attempting to access its Count causes evaluation, and that times out with error (e.g. "The Server is not operational" if disconnected).