/// <summary>
/// Sets the member of dom specified by name to null.
/// If a member with the specified name does not exist an ArgumentException will be thrown.
/// </summary>
public void SetNull(DocumentObject dom, string name)
{
ValueDescriptor vd = _vds[name];
if (vd == null)
{
throw new ArgumentException(DomSR.InvalidValueName(name));
}
vd.SetNull(dom);
}