DataGridView filter with BindingSource?

Hi,

Been searching the web for a couple days, trying various examples but can't seem to get this to work.  I have a form with a DataGridView.  I pass the form a reference to my data access layer class, which contains a method that returns a dataset that contains a datatable called Patients.

I'm using a BindingSource as the DataSource of the DataGridView and some TextBox objects on the form.  The intent being that when the user clicks on a record in the DataGridView, the details appear in the TextBoxes.  This part is working fine.

I also have another TextBox that I'm trying to use to filter the DataGridView and this is the part I can't get to work.  It compiles without error but it just doesn't work, nothing seems to happen to the data displayed.

Here's my code:

public partial class frmPatientSelection : Form
{
        public DataTable dtPatients { get; set; }
        public DataSet dsPatients { get; set; }
        DeliveryMgrDALDisLayer _dal = null;
        BindingSource bs = new BindingSource();

        public frmPatientSelection()
        {
            InitializeComponent();
        }

        public frmPatientSelection(DeliveryMgrDALDisLayer dal)
        {
            InitializeComponent();
            _dal = dal;
        }

        private void frmPatientSelection_Load(object sender, EventArgs e)
        {
            // Get the active patient data.
            dsPatients = _dal.GetActivePatients();
            
            // Set the binding source.
            bs.DataSource = dsPatients;

            // Set the DataGridView data source.
            dgvPatients.DataSource = bs;
            dgvPatients.DataMember = "Patients";

            // Setup text box data sourcse.
            txtPatientName.DataBindings.Add("Text", bs, "Patients.Patient");
            txtDestination.DataBindings.Add("Text", bs, "Patients.Primary Addr");
        }

        private void txtFind_TextChanged(object sender, EventArgs e)
        {
            bs.Filter = string.Format("[patient id] LIKE '{0}'", txtFind.Text);
        }
    }
}

All of the examples I've found online are basically this approach, but it simply doesn't work.

I did have some success without the BindingSource, using a DataTable as the DataSource for the DataGridView, but all of the examples I found for binding the TextBoxes to the DataGridView used the BindingSource.

Any thoughts as to what I'm missing?

Thanks in advance!