Getting object name instead of value from LDAP query

After doing a search I located a post with a similar title as above and wanted to create a new post to aid in finding information.

Here is the offending code:

<code>
    Sub getEmailList()
        sPath = "LDAP://my.domain.local"
            'Setup Datatable
        Dim table As New DataTable("Results")
        table.Columns.Add("Last Name")
        table.Columns.Add("First Name")
        table.Columns.Add("Email Address")
        Dim row As DataRow
        'Setup AD Query
        Dim de As New DirectoryServices.DirectoryEntry(sPath, "USERNAME", "PASSWORD")
        Dim dSearch As New DirectoryServices.DirectorySearcher(de, "(&(objectClass=user)(objectCategory=person))")
        dSearch.PropertiesToLoad.Add("sn")
        dSearch.PropertiesToLoad.Add("givenName")
        dSearch.PropertiesToLoad.Add("mail")
        'Loop and build Table

        Dim mySearchResult As DirectoryServices.SearchResult
        Dim mySearchResultColl As DirectoryServices.SearchResultCollection
        Dim myResultPropColl As DirectoryServices.ResultPropertyCollection
        Dim myResultPropValueColl As DirectoryServices.ResultPropertyValueCollection
        Dim propVal() As String
        Dim counter As Integer
        mySearchResultColl = dSearch.FindAll()
        For Each mySearchResult In mySearchResultColl
                row = table.NewRow()
                row("Last Name") = mySearchResult.Properties("sn")
                row("First Name") = mySearchResult.Properties("givenName")
                row("Email Address") = mySearchResult.Properties("mail")
                table.Rows.Add(row)
        Next
            DataSet1.Tables.Add(table)
            DataView1.Table = DataSet1.Tables("Results")
            'DataView1.Sort = "Last Name"
            'Databind to dataset.
            DataGrid1.DataSource = DataSet1
            DataGrid1.DataBind()
    End Sub
</code>

When I run this, the DataGrid is populated, but all I see is: System.DirectoryServices.ResultPropertyValueCollection in the three columns. When I change:
<code>
mySearchResult.Properties("sn")
</code>
to this:
<code>
mySearchResult.Properties("sn")(0).ToString()
</code>

I get the following error:

System.NullReferenceException: Object reference not set to an instance of an object.

I only want those three properties of the user to show up in the DataGrid and nothing else. Am I getting this error because I need to loop through the Properties? If so, how do I do this? I have tried using a counter with a Do While, counter = counter +1 but get the same Object reference error as above.

Any assistance would be greatly appreciated.

Re: Getting object name instead of value from LDAP query

Anyone? This is a current project so any help would be nice!

Re: Getting object name instead of value from LDAP query

You just need to check if the value exists first. It would be something like this:

if (sr.Properties.Contains("attribute))
{
    //safe to access now
    sr.Properties["attribute"][0].ToString();
}

The 'null' reference occurs when the attribute is not on the object. I would suggest defining the attributes you are after in a string array and then applying the pattern above in a loop as you iterate over the string array. A full example of this that generically builds DataSets was available in an older post that looks to have been archived now. I will include the code for it here so we can build the knowledge again. Use your favorite translator for VB.NET:

public DataSet FindUsers(string sFilter, string[] columns, string path, bool useCached)
{
    //try to retrieve from cache first
    HttpContext context = HttpContext.Current;
    DataSet userDS = (DataSet)context.Cache[sFilter];

    if((userDS == null) || (!useCached))
    {
        //setup the searching entries
        DirectoryEntry deParent = new DirectoryEntry(path);
        //deParent.Username = Config.Settings.UserName;
        //deParent.Password = Config.Settings.Password;
        deParent.AuthenticationType = AuthenticationTypes.Secure;

        DirectorySearcher ds = new DirectorySearcher(deParent,sFilter,columns);
        ds.PageSize = 1000;

        using(deParent)
        {
            //setup the dataset that will store the results
            userDS = new DataSet("userDS");
            DataTable dt = userDS.Tables.Add("users");
            DataRow dr;

            //add each parameter as a column
            foreach(string prop in columns)
            {
                dt.Columns.Add(prop, typeof(string));
            }

            using (SearchResultCollection src = ds.FindAll())
            {
                foreach(SearchResult sr in src)
                {
                    dr = dt.NewRow();
                    foreach(string prop in columns)
                    {
                        if(sr.Properties.Contains(prop))
                        {
                            dr[prop] = sr.Properties[prop][0];
                        }
                    }
                    dt.Rows.Add(dr);
                }
            }
        }
        //cache it for later, with sliding 3 minute window
        context.Cache.Insert(sFilter, userDS, null, DateTime.MaxValue, TimeSpan.FromSeconds(180));
    }
    return userDS;
}

Now, just place a datagrid on your page, and with a few lines of code, you have a searcher:

//sample use
string qry = String.Format("(&(objectCategory=person)(givenName={0}*))", txtFirstName.Text);
string[] columns = new string[]{"givenName", "sn", "cn", "sAMAccountName", "telephoneNumber", "l"}
string ldapPath = "LDAP://dc=mydomain";

DataSet ds = FindUsers(qry, columns, ldapPath, true);
DataGrid1.DataSource = ds;
DataGrid1.DataBind();

If you were really clever, you would dynamically create the ldap query and just keep passing in a new one. Alternatively, you could get some good performance wins by using a larger filter result set and caching the DataSet from the method (longer than 3 minutes hopefully), and then using the DataView.RowFilter to filter the cached DataSet before binding to DataGrid. It would then never need to talk to AD again until you wanted to invalidate the cache.

Re: Getting object name instead of value from LDAP query

Bleh that post turned out rather interesting.

The goal is for a user to go to the web page and see the most uptodate information on the Email addresses listed in Active Directory. So basically the page needs to iterate through all of the OUs and list out every single user's First Name, Last Name, and Email Address. I guess I'll have to fish through the code you posted and figure out how to translate it into VB.NET using VS.NET2003.

Thanks for the help I'll see what I can do.

Re: Getting object name instead of value from LDAP query

There are a number of translators that will convert that for you. To do what you want using the FindUsers() method as I presented it, you would do this:

//sample use
string qry = "(&(objectCategory=person)(objectClass=user)"; //all users
string[] columns = new string[]{"givenName", "sn", "mail"}; //first, last, email
string ldapPath = "LDAP://dc=mydomain,dc=com"; //point to your root domain to get all users

//hope you are using Paging in your DataGrid - this could be big!!
DataSet ds = FindUsers(qry, columns, ldapPath, true);
DataGrid1.DataSource = ds;
DataGrid1.DataBind();

Easy 'nuf.

Re: Getting object name instead of value from LDAP query

dunnry,

Thank you again for your post. I was able to get the necessary information from AD thanks to your code. I do have a couple more questions though:

1. At what point in the code can I sort the results by givenName? I get the list with several blank entries where there is an sn, givenName, but no email address (none was entered in AD). Can I sort these results by givenName so I can determine who has addresses and who doesn;t?

2. In your code you use
            'deParent.Username = Config.Settings.UserName;
            'deParent.Password = Config.Settings.Password;
I'm assuming this information is being pulled from the web.config file. Do you perchance know the syntax inside the web.config file where I need to put this?

Thanks!

Re: Getting object name instead of value from LDAP query

Got the answer to my first question already:

Added the following:

'**********************************************
'Sort the list by givenName (First Name)
'Other options are: sn, mail
ds.Sort.PropertyName = "givenName"

I also found the answer to another question. It appears that with LDAP you can't tell the query to NOT include NULL values. For example, if I query AD for all users, and get accounts that do not have a value for sn, I am unable to specify the following:

!sn=null or \00

You can only query for attributes that MUST have a value:

sn=*

The above will only return results where sn has a value.

Re: Getting object name instead of value from LDAP query

[quote user="dunnry"]There are a number of translators that will convert that for you. To do what you want using the FindUsers() method as I presented it, you would do this:

//sample use
string qry = "(&(objectCategory=person)(objectClass=user)"; //all users
string[] columns = new string[]{"givenName", "sn", "mail"}; //first, last, email
string ldapPath = "LDAP://dc=mydomain,dc=com"; //point to your root domain to get all users

//hope you are using Paging in your DataGrid - this could be big!!
DataSet ds = FindUsers(qry, columns, ldapPath, true);
DataGrid1.DataSource = ds;
DataGrid1.DataBind();

Easy 'nuf.

Do I have to know exactly what the objectCategory, objectClass, givenName, sn, and mail to use the FindUsers? I tried it and I got this error.

The (&(objectCategory=person)(objectClass=user) search filter is invalid.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.ArgumentException: The (&(objectCategory=person)(objectClass=user) search filter is invalid.

Source Error:

Line 56:                 using (SearchResultCollection src = ds.FindAll())
Line 57:                 {
Line 58:                     foreach (SearchResult sr in src)
Line 59:                     {
Line 60:                         dr = dt.NewRow();

If I do, how do I find those out?

Re: Getting object name instead of value from LDAP query

Any other idea? Help is still needed.

Re: Getting object name instead of value from LDAP query

i tried using your code but but iam getting an error

Error 1 'FindUsers': member names cannot be the same as their enclosing type.

What might be the problem??

Getting LDAP entries into a gridview

Iam new to asp.net and Iam trying to bring my LDAP values on to a grid view. When I run my application iam not able to see the grid (the page turns up empty) what could be the possible reason??

public DataSet Userlogin(string sFilter, string[] columns, string path, bool useCached)

{

// trying to retrieve data from cache

string ulid = Session["id"].ToString();

string password = Session["password"].ToString();

HttpContext context = HttpContext.Current;

DataSet usersDS = (DataSet)context.Cache[sFilter];

if ((usersDS == null) || (!useCached))

{

//setup searching entries

DirectoryEntry deParent = new DirectoryEntry(path, ulid, password);

deParent.AuthenticationType = AuthenticationTypes.Secure;

DirectorySearcher ds = new DirectorySearcher(deParent, sFilter, columns);

ds.PageSize = 1000;

using (deParent)

{

//setup dataset that will store the results

usersDS = new DataSet("userDS");

DataTable dt = usersDS.Tables.Add("users");

DataRow dr;

// adding each property as a column

foreach (string prop in columns)

{

dt.Columns.Add(prop, typeof(string));

}

using (SearchResultCollection src = ds.FindAll())

{

foreach (SearchResult sr in src)

{

dr = dt.NewRow();

foreach (string prop in columns)

{

if (sr.Properties.Contains(prop))

{

dr[prop] = sr.Properties[prop][0];

}

dt.Rows.Add(dr);

}

// cache it for later, with 3 minutes sliding window

context.Cache.Insert(sFilter, usersDS, null, DateTime.MaxValue, TimeSpan.FromSeconds(180));

}

return usersDS;

}

protected void Page_Load(object sender, EventArgs e)

{

lblulid.Text = Session["id"].ToString();

string username = Session["id"].ToString();

string query = "(|(cn=" + username + ") (userPrincipalName= " + username + "ad.ilstu.edu))";

string[] columns = new string[] { "givenname", "sn", "physicalDeliveryOfficeName", "telephoneNumber", "mail", "cn" };

string ldapPath = "LDAP:// ";

GridView1.Visible = true;

DataSet ds = Userlogin(query, columns, ldapPath, true);

GridView1.DataSource = ds;

GridView1.DataBind();

}

<asp:GridView ID="GridView1" runat="server" AllowPaging="True" AllowSorting="True"

AutoGenerateColumns="true" CellPadding="4" ForeColor="#333333" GridLines="None"

Style="z-index: 100; left: 161px; position: absolute; top: 211px" EnableViewState="true" >