filtering gridview by calling seach method from bll in code behind (probably simple fix)

private DataTable GridDataSource()
   {
       personsBAL pBAL = new personsBAL();
       personBO pBO = new personBO();
       DataTable dTable = new DataTable();
       try
       {
           pBO.personName = personName.ToString(); //textbox
           pBO.personLast = personLast.ToString(); //textbox
           pBO.genderID = Convert.ToInt32(genderDDL); //there's a dropdownlist
           pBO.ethnicityID = Convert.ToInt32(ethnicityDDL); //there's a dropdownlist
           pBO.personAge = int.Parse(personAge.Text); //textbox

           dTable = pBAL.Search(personName, personLast, genderID, genderDDL, ethnicityDDL, personAge);
       }
       catch (Exception ee)
       {
           lblMessage.Text = ee.Message.ToString();
       }
       finally
       {
           personBAL = null;
       }

       return dTable;
   }

ALTER PROCEDURE SearchAllPersons
	(
		@personID int,
		@personName varchar(50),
		@personLast varchar(50),
		@genderID int,
		@ethnicityID int,
		@personAge int
	)
AS
	/* SET NOCOUNT ON */
SELECT DISTINCT 
                         person.personID, person.personName, person.personLast, person.genderID, gender.gender, person.ethnicityID, 
                         ethnicity.ethnicity, person.personAge

FROM            person INNER JOIN
                         gender ON person.genderID = gender.genderID INNER JOIN
                         ethnicity ON person.ethnicityID = ethnicity.ethnicityID

WHERE        (person.personName LIKE '%'+ @personName +'%'OR @personName IS NULL) AND (person.personLast LIKE '%' + @personLast + '%' OR
                         @personLast IS NULL) AND (person.genderID = @genderID OR
                         0 = @genderID) AND (person.ethnicityID = @ethnicityID OR
                         0 = @ethnicityID) AND (person.personAge = @personAge OR
                         0 = @personAge)
	RETURN

/// <summary>
/// Search all records from database
/// </summary>
/// <returns></returns>
public DataTable SearchByAll()
{
    SqlConnection conn = new SqlConnection(connSTR);
    SqlDataAdapter personSearch = new SqlDataAdapter("SearchAllPersons", conn);
    SearchAllPersons.SelectCommand.CommandType = CommandType.StoredProcedure;
    DataSet dSet = new DataSet();
    try
    {
        SearchAllPersons.Fill(dSet, "personTable"); //what is personTable?
        return dSet.Tables["personTable"]; //what is personTable?
    }
    catch
    {
        throw;
    }
    finally
    {
        dSet.Dispose();
        SearchAllPersons.Dispose();
        conn.Close();
        conn.Dispose();
    }
}

/// <summary>
/// Search records from database
/// </summary>
/// <returns></returns>
public DataTable Search(string personName, string personLast, int genderID, int ethnicityID, int personAge)
{
    personsDAL pDAL = new personsDAL();
    try
    {
        return Search(personName, personLast, genderID, ethnicityID, personAge);
    }
    catch
    {
        throw;
    }
    finally
    {
        personsDAL = null;
    }
}

/// <summary>
/// Summary description for personsBO
/// </summary>
public class personsBO
{
	public personsBO()
	{
	}

    private string personName_BO;
    private string personLast_BO;
    private int genderID_BO;
    private int ethnicityID_BO;
    private int personAge_BO;


    public string personName
    {
        get
        {
            return personName_BO;
        }
        set
        {
            if (value == null)
            {
                throw new Exception("Must type in name"); //this didn't work...learning how to throw exceptions...
            }
            else
            {
                personName_BO = value;
            }
        }
    }

    public string personLast
    {
        get
        {
            return personLast_BO;
        }
        set
        {
            if (value == null)
            {
                throw new Exception("Must type in name"); //still didn't work...any pointers?
            }
            else
            {
                personLast_BO = value;
            }
        }
    }


    public int genderID
    {
        get
        {
            return genderID_BO;
        }
        set
        {
            genderID_BO = value;
        }
    }

    public int ethnicityID
    {
        get
        {
            return ethnicityID_BO;
        }
        set
        {
            ethnicityID_BO = value;
        }
    }

    public int personAge
    {
        get
        {
            return personAge_BO;
        }
        set
        {
            personAge_BO = value;
        }
    }

   /* public DateTime timeInsert
    {
        get
        {
            return timeInsert_BO;
        }
        set
        {
            timeInsert_BO = DateTime.Now.ToString;
        }
    }*/
}

<form id="form1" runat="server">

<div> //in this div...there are the controls for the filters
   personNameTextBox
   personLastTextBox
   ethnicityDropDownList
   genderDropDownList
   personAgeTextBox
</div>

<div>
    <p><a href="Default.aspx">Add Record</a></p>
    <asp:Label ID="lblMessage" runat="Server" ForeColor="red" EnableViewState="False"></asp:Label>
    <asp:GridView ID="GridView1" runat="server" CellPadding="4" ForeColor="#333333" GridLines="None"
     DataKeyNames="PersonID" AutoGenerateEditButton="True" AutoGenerateColumns="False"
      OnRowEditing="EditRecord" OnRowUpdating="UpdateRecord" OnRowCancelingEdit="CancelRecord"
       OnRowDeleting="DeleteRecord" AllowPaging="True" AllowSorting="true" PageSize="5"
       OnPageIndexChanging="ChangePage" OnSorting="SortRecords">
        <FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
        <RowStyle BackColor="#EFF3FB" />
        <EditRowStyle BackColor="#2ff1BF" />
        <SelectedRowStyle BackColor="#D1DDF1" Font-Bold="True" ForeColor="#333333" />
        <PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" />
        <HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
        <AlternatingRowStyle BackColor="White" />
        <Columns>
            <asp:BoundField DataField="PersonID" HeaderText="Person ID" Visible="false" ReadOnly="True"  SortExpression="PersonID" />

            <asp:TemplateField HeaderText="First Name" SortExpression="personName">
                <ItemTemplate>
                    <%# Eval("personName") %>
                </ItemTemplate>
            </asp:TemplateField>

            <asp:TemplateField HeaderText="Last Name" SortExpression="personLast">
                <ItemTemplate>
                    <%# Eval("personLast") %>
                </ItemTemplate>
                </asp:TemplateField>

            <asp:TemplateField HeaderText="genderID" Visible="false">
                <ItemTemplate>
                    <%# Eval("genderID") %>
                </ItemTemplate>
                </asp:TemplateField>

            <asp:TemplateField HeaderText="Gender" SortExpression="gender">
                <ItemTemplate>
                    <%# Eval("gender") %>
                </ItemTemplate>
                </asp:TemplateField>

            <asp:TemplateField HeaderText="ethnicityID" Visibility="false">
                <ItemTemplate>
                    <%# Eval("ethnicityID") %>
                </ItemTemplate>
                </asp:TemplateField>

            <asp:TemplateField HeaderText="Ethnicity" SortExpression="ethnicity">
                <ItemTemplate>
                    <%# Eval("ethnicity") %>
                </ItemTemplate>
                </asp:TemplateField>

            <asp:TemplateField HeaderText="Age" SortExpression="Age">
                <ItemTemplate>
                    <%# Eval("personAge") %>
                </ItemTemplate>
                </asp:TemplateField>

            <asp:TemplateField HeaderText="Delete?">
                <ItemTemplate>
                    <span  önclick="return confirm('Are you sure to Delete?')">
                        <asp:LinkButton ID="lnBD" runat="server" Text="Delete" CommandName="Delete"></asp:LinkButton>
                    </span>
                </ItemTemplate>
            </asp:TemplateField>

        </Columns>
    </asp:GridView>
</div>
</form>

public partial class Default: System.Web.UI.Page
{

    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
            BindGrid();
    }
    protected void Button1_Click(object sender, EventArgs e) //oh yea...there's a button...
    {
        if (!IsPostBack)
            BindGrid();

    }

    /// <summary>
    /// Fires when page links are clicked
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void ChangePage(object sender, GridViewPageEventArgs e)
    {
        GridView1.PageIndex = e.NewPageIndex;
        // Refresh the list
        BindGrid();
    }

    /// <summary>
    /// Fires when Columns heading are clicked
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void SortRecords(object sender, GridViewSortEventArgs e)
    {
        DataTable dataTable = GridDataSource();

        if (dataTable != null)
        {
            DataView dataView = new DataView(dataTable);

            dataView.Sort = GetSortExpression(e);

            GridView1.DataSource = dataView;
            GridView1.DataBind();
        }
    }


    #region Private Methods

    /// <summary>
    /// Bind the gridview
    /// </summary>
    private void BindGrid()
    {
        GridView1.DataSource = GridDataSource();
        GridView1.DataBind();
    }

    /// <summary>
    /// Get GridView DataSource
    /// </summary>
    private DataTable GridDataSource()
    {
        personsBAL pBAL = new personsBAL();
        personBO pBO = new personBO();
        DataTable dTable = new DataTable();
        try
        {
            pBO.personName = personName.ToString(); //textbox
            pBO.personLast = personLast.ToString(); //textbox
            pBO.genderID = Convert.ToInt32(genderDDL); //there's a dropdownlist
            pBO.ethnicityID = Convert.ToInt32(ethnicityDDL); //there's a dropdownlist
            pBO.personAge = int.Parse(personAge.Text); //textbox

            dTable = pBAL.Search(personName, personLast, genderID, genderDDL, ethnicityDDL, personAge);
        }
        catch (Exception ee)
        {
            lblMessage.Text = ee.Message.ToString();
        }
        finally
        {
            personBAL = null;
        }

        return dTable;
    }

    /// <summary>
    /// Get sort expression for the gridview
    /// </summary>
    /// <param name="e"></param>
    /// <returns></returns>
    private string GetSortExpression(GridViewSortEventArgs e)
    {
        string sortDirection = string.Empty;
        // if clicked on the same column twice then let it toggle the sort order, else reset to ascending
        if (ViewState["SortExpression"] != null)
        {
            if (!ViewState["SortExpression"].ToString().Equals(e.SortExpression.ToLower()))
            {
                ViewState["SortDirection"] = null;
            }
        }

        if (ViewState["SortDirection"] != null)
        {
            if (ViewState["SortDirection"].ToString().Equals("ASC"))
            {
                sortDirection = "DESC";
                ViewState["SortDirection"] = "DESC";
            }
            else
            {
                sortDirection = "ASC";
                ViewState["SortDirection"] = "ASC";
            }
        }
        else
        {
            ViewState["SortDirection"] = "ASC";
        }
        ViewState["SortExpression"] = e.SortExpression.ToLower();

        return e.SortExpression + " " + sortDirection;
    }
    #endregion Private Methods

}