protected void btnApply_Click(object sender, EventArgs e)
    {
        //create an instance of the class collection
        clsServicesCollection Services = new clsServicesCollection();

        Services.ServiceByStaff(txtStaff.Text);
        lstServiceList.DataSource = Services.ServiceList;

        //set the name of the primary key
        lstServiceList.DataValueField = "Service Name";

        //set the name of the field to display
        lstServiceList.DataTextField = "Staff";

        //bind the data to the list
        lstServiceList.DataBind();
    }
    protected void btnClear_Click(object sender, EventArgs e)
    {
        clsServicesCollection Services = new clsServicesCollection();

        Services.ServiceByStaff("");

        //clear any existing filter to tidy up the interface
        txtStaff.Text             = "";
        lstServiceList.DataSource = Services.ServiceList;

        //set the name of the primary key
        lstServiceList.DataValueField = "Service Name";

        //set the name of the field to display
        lstServiceList.DataTextField = "Staff";

        //bind the data to the list
        lstServiceList.DataBind();
    }