Help with sqldatasource parameters and passing the value

[binici]

Hello:
I have come to a tricky part of my webproject. This maybe a bit confusing.
As of now I have two sqldatasources:

<asp:SqlDataSource ID="sqlBrokersAgentsRecips" runat="server" ConnectionString="<%$ AppSettings:connectionstring %>" ProviderName="System.Data.SqlClient" SelectCommandType="StoredProcedure" SelectCommand="callcenterdev..spGetBrokersAgentsForRecips">
    <SelectParameters>
        <asp:Parameter Name="OfficeId" DefaultValue="88430760" />
    </SelectParameters>
</asp:SqlDataSource>
<asp:SqlDataSource  ID="sqlMembersOfficeId" runat="server" ConnectionString="<%$ AppSettings:connectionstring %>" ProviderName="System.Data.SqlClient" SelectCommandType="Text" SelectCommand="SELECT m.Office_Number FROM rapdata..Member m WITH(NOLOCK) WHERE Member_Number = @sesBrokerId">
    <SelectParameters>
        <asp:SessionParameter SessionField="sesBrokerId" Name="sesBrokerId" />
    </SelectParameters>
</asp:SqlDataSource>

The sqlMembersOfficeId retrieves the office_number I need correctly, (I know because I have checked the db value and have outputted the value on a label control).
Now the tricky part I am trying to understand is, I need the office_id to be passed for the sqlBrokersAgentsRecips (as you can see I just manually add the value for now to test). Upon doing so I will be able to bind a dropdownlist with the correct members within the office_number.

<asp:DropDownList ID="BrokerAgentNamesDD" runat="server" DataSourceID="sqlBrokersAgentsRecips" DataTextField="Agent_Name" DataValueField="Member_Number">
</asp:DropDownList>

I know in asp 3.0 you could just sub out all your stored procedures and call them anytime, but looks like its much more elaborate in .NET.
Thanks for your help!

 

[binici]

I was doing some reading and it looks like I may need to use SqlDataSourceStatusEventArgs for add the output to a control, variable, ect?