Making GetObject work for LDAP

[Atul Kale]

Hi guys
I am wkg on a C# Component which retrieves information from the ADS on Win2k Domain. For some reason, instead of using the System.DirectoryServices namespace, I have to go for the ADS Library (a COM DLL).

To write the code in VB.NET I can go ahead and use the GetObject Global method of VB. as following...

Dim objLDAP as ActiveDS.IAdsOpenDSObject objLDAP = GetObject("LDAP:")
' Here it uses the Global GetObject method,
' that specifies the First param as path and...
' NO ProgID as it is Optional Param.

In C#, I cannot use the same global function, hence the alternative, Activator.GetObject can be used. But it does not retrieve the reference at all.
I even tried, Specifically giving the Type param to the Method as...

IAdsOpenDSObject objLDAP; objLDAP = Activator.GetObject(typeof(ActiveDS.IAdsOpenDSObject), "LDAP:");

This ends up in giving error message saying that,
A Proper link to the Service may not have been established correctly. How can I make this work, as I must have all my Components in C# only. Porting this part in VB.NEt only for this reason would be infeasible.

Please help me out in this. Atul Kale Sr. Software Engineer. XcelVision Technologies Ltd.

[Richard Deeming]

You really should be using System.DirectoryServices for this, and only resorting to the ADSI library as a last resort. The Activator.GetObject is not related to the VB GetObject function. To replace the VB functionality, you can either use the Microsoft.VisualBasic.Interaction.GetObject function, or use a combination of the BindToMoniker and GetActiveObject functions from the System.Runtime.InteropServices.Marshal class.

using System;
using System.Runtime.InteropServices;

public class ComUtils
{
public static object GetObjectFromClass(string className)
{
object ret = Marshal.GetActiveObject(className);

    if (null == ret)
    {
        // **NB:** Not sure if this is needed,
        // but the GetActiveObject functions should
        // only return an existing object, not
        // create a new instance.
        Type t = Type.GetTypeFromProgID(className);
        ret = Activator.CreateInstance(t);
    }
    
    return ret;
}

public static object GetObject(string pathName)
{
    return Marshal.BindToMoniker(pathName);
}

public static object GetObject(string pathName, string className)
{
    if (null == pathName || 0 == pathName.Length)
    {
        return GetObjectFromClass(className);
    }
    else if (null == className || 0 == className.Length)
    {
        return Marshal.BindToMoniker(pathName);
    }
    else
    {
        // Class and path specified
        object ret = GetObjectFromClass(className);
        
        UCOMIPersistFile pf = (UCOMIPersistFile)ret;
        pf.Load(pathName, 0);
        
        return pf;
    }
}

}

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"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

[Atul Kale]

Hi Richard, Thanx a lot for that code! In fact I had tried all the possible combinations of using Type.GetTypeFromProgID and then calling the Activator.GetObject etc. etc. But the most important thing I forgot was about the Binding part. I had been wkg on VC++ with Monikers many a times, I just never thought I would need them here too.
regards Atul Kale MCSD, MCT Sr. Software Engineer XcelVision Technologies Ltd.