C# and VB.NET LDAP Search Different?

Question

Does anyone know if there is a difference between the implementation of the FindAll() method on the DirectorySearcher object in C# and VB.NET? From my understanding they both get "compiled" to MSIL and get processed by the CLR the same way. Going against our ADAM/LDAP system the below C# code throws an error and the below VB.NET does not.

Here is the C# exception stack:

at System.DirectoryServices.DirectoryEntry.Bind(Boolean throwIfFail)
  at System.DirectoryServices.DirectoryEntry.Bind()
  at System.DirectoryServices.DirectoryEntry.get_AdsObject()
  at System.DirectoryServices.DirectorySearcher.FindAll(Boolean findMoreThanOne)
  at System.DirectoryServices.DirectorySearcher.FindAll()

Here is the C# error:

System.Runtime.InteropServices.COMException was unhandled
Message="The parameter is incorrect.\r\n"
Source="System.DirectoryServices"
ErrorCode=-2147024809

C# code:

private void button1_Click(object sender, EventArgs e)
{
    DirectoryEntry root = new DirectoryEntry("LDAP://directory.corp.com/OU=Person,OU=Lookups,O=Corp,C=US", null, null, AuthenticationTypes.Anonymous);
    DirectorySearcher mySearcher = new DirectorySearcher(root);

    mySearcher.Filter = "(uid=ssnlxxx)";
    mySearcher.PropertiesToLoad.Add("cn");
    mySearcher.PropertiesToLoad.Add("mail");

    SearchResultCollection searchResultCollection = null;
    searchResultCollection = mySearcher.FindAll(); //this is where the error occurs

    try
    {
        foreach (SearchResult resEnt in searchResultCollection)
        {
            Console.Write(resEnt.Properties["cn"][0].ToString());
            Console.Write(resEnt.Properties["mail"][0].ToString());
        }
    }
    catch (DirectoryServicesCOMException ex)
    {
        MessageBox.Show("Failed to connect LDAP domain, Check username or password to get user details.");
    }
}

This is the VB.NET code that works:

Private Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click

    Dim root As New     DirectoryEntry("LDAP://directory.corp.com/OU=People,OU=Lookups,O=corp,C=US", vbNull, vbNull, authenticationType:=DirectoryServices.AuthenticationTypes.Anonymous)
    Dim searcher As New DirectorySearcher(root)
    searcher.Filter = "(uid=ssnlxxx)"
    searcher.PropertiesToLoad.Add("cn")
    searcher.PropertiesToLoad.Add("mail")

    Dim results As SearchResultCollection

    Try
        results = searcher.FindAll()

        Dim result As SearchResult
        For Each result In results
            Console.WriteLine(result.Properties("cn")(0))
            Console.WriteLine(result.Properties("mail")(0))
        Next result
    Catch ex As Exception
        MessageBox.Show("There was an error")
    End Try
End Sub

Answer 1

I am going to guess that in the VB.NET code, you're passing in vbNull (instead of Nothing ) for two parameters in the DirectoryEntry constructor, and in the C# code you're passing null . vbNull is presumably from the evil Microsoft.VisualBasic assembly which should not be used.

The constructor for DirectoryEntry checks the username and password parameters to see if they're null. If vbNull != Nothing , the constructor won't treat them as null and will behave differently.

See if the VB.NET code throws the exception if you use Nothing , or alternatively see if the C# code works by using String.Empty instead of null .

Also, in your C# code, the call to FindAll is outside of the try block.

Answer 2

Neither C# nor VB.NET implement DirectorySearcher or any other part of .NET. They are all part of the .NET Framework.