private void RetrieveDataFolder()
{
    SoapClient framework = new SoapClient();
    framework.ClientCredentials.UserName.UserName = "xxx";
    framework.ClientCredentials.UserName.Password = "xxx";
    String requestID;
    String status;
    APIObject[] results;
    SimpleFilterPart sfp = new SimpleFilterPart();
    sfp.Property = "ContentType";
    sfp.SimpleOperator = SimpleOperators.equals;
    sfp.Value = new string[] { "email" };
    RetrieveRequest rr = new RetrieveRequest();
    rr.ObjectType = "DataFolder";
    rr.Properties = new string[] { "ID", "Name", "ParentFolder.ID","ParentFolder.Name" };
    rr.Filter = sfp;
    status = framework.Retrieve(rr, out requestID, out results);
    Console.WriteLine(status);
    foreach (DataFolder df in results)
    {
Console.WriteLine("---------");
Console.WriteLine("Folder Name: " + df.Name);
Console.WriteLine("Folder ID: " + df.ID);
Console.WriteLine("Parent Folder Name: " + df.ParentFolder.Name);
Console.WriteLine("Parent Folder ID: " + df.ParentFolder.ID);
    }
}