/// <summary>
/// Gets 0 or 1 or many attributes with the specified OID.
/// </summary>
/// <param name="attributes">A collection of attributes.</param>
/// <param name="oid">The attribute OID to search for.</param>
/// <returns>Either a <see cref="CryptographicAttributeObject" /> or <c>null</c>, if no attribute was found.</returns>
/// <exception cref="ArgumentNullException">Thrown if <paramref name="attributes" /> is <c>null</c>.</exception>
/// <exception cref="ArgumentException">Thrown if <paramref name="oid" /> is either <c>null</c> or an empty string.</exception>
public static IEnumerable <CryptographicAttributeObject> GetAttributes(this CryptographicAttributeObjectCollection attributes, string oid)
{
if (attributes == null)
{
throw new ArgumentNullException(nameof(attributes));
}
if (string.IsNullOrEmpty(oid))
{
throw new ArgumentException(Strings.ArgumentCannotBeNullOrEmpty, nameof(oid));
}
return(attributes.Cast <CryptographicAttributeObject>()
.Where(attribute => attribute.Oid.Value == oid));
}