jQuery Grid Plugin - jqGrid

Here is my problem.  I can populate data into the jqGrid via a Objectdatasource on page load.  I also have a dropdownlist that has 4 options to choose from.  When I try to code the Grid to reload the data when a dropdownlist select is made, the data remains.  I want to be able to make a selection in the dropdown and that will reload the grid with different data.  It works fine in a normal grid, but for some reason jqGrid doesn't like to work.  Any ideas????

Here is the code I'm working with...

 public partial class Employees : System.Web.UI.Page
    {
        Employee newEmp = new Employee();

        protected void Page_Load(object sender, EventArgs e)
        {
            empGrid.DataSource = employeeODS;
            empGrid.DataBind();
        }

        protected void siteDropDownList_SelectedIndexChanged1(object sender, EventArgs e)
        {
            empGrid.DataSource = ObjectDataSource1;
            empGrid.DataBind();
        }

and my jqGrid code...

<cc1:JQGrid ID="empGrid" runat="server" Width="484px" Height="241px">
    <Columns>
    <cc1:JQGridColumn DataField="DisplayName" HeaderText="Employee Name" Width="115"></cc1:JQGridColumn>
    <cc1:JQGridColumn DataField="EmployeeID" HeaderText="MyID" Width="50"></cc1:JQGridColumn>
    <cc1:JQGridColumn DataField="Title" HeaderText="Title" Width="115"></cc1:JQGridColumn>
    </Columns>
    <SearchToolBarSettings SearchToolBarAction="SearchOnKeyPress" />
    <PagerSettings ScrollBarPaging="true" PageSize="100" />
    <ToolBarSettings ShowSearchToolBar="true" ></ToolBarSettings>
    <AppearanceSettings HighlightRowsOnHover="true" ScrollBarOffset="16" />
    </cc1:JQGrid>

my Objectdatasource....

 <asp:ObjectDataSource ID="employeeODS" runat="server"
    SelectMethod="GetEmployeeInfo" TypeName="Website.Employee">
    </asp:ObjectDataSource>

    <asp:ObjectDataSource ID="ObjectDataSource1" runat="server"
    SelectMethod="GetEmployeeBySite" TypeName="Website.Employee">
    <SelectParameters>
    <asp:ControlParameter ControlID="siteDropDownList" Name="Location"
            PropertyName="SelectedValue" Type="String"  />
    </SelectParameters>
    </asp:ObjectDataSource>