Project project = new Project("New Project.mpp");

// Read extended attributes for tasks
foreach (Task task in project.RootTask.Children)
{
    foreach (ExtendedAttribute ea in task.ExtendedAttributes)
    {
        Console.WriteLine(ea.FieldId);
        Console.WriteLine(ea.ValueGuid);

        switch (ea.AttributeDefinition.CfType)
        {
            case CustomFieldType.Date:
            case CustomFieldType.Start:
            case CustomFieldType.Finish:
                Console.WriteLine(ea.DateValue);
                break;

            case CustomFieldType.Text:
                Console.WriteLine(ea.TextValue);
                break;

            case CustomFieldType.Duration:
                Console.WriteLine(ea.DurationValue.ToString());
                break;

            case CustomFieldType.Cost:
            case CustomFieldType.Number:
                Console.WriteLine(ea.NumericValue);
                break;

            case CustomFieldType.Flag:
                Console.WriteLine(ea.FlagValue);
                break;
        }
    }
}