I have a grid where you can select items, a drop down and a button. You can select an action from the dropdown and the click the button to open the modal dialog. I need to put the id of the selected items in the Session first (IMPORTANT!), and then I need to open a Modal Dialog from code behind. I have tried a few solutions but the client code always get executed before the server code.

Thanks in advance,

UPDATE

This is the code in the aspx page

<telerik:RadComboBox ID="rcActions" runat="server" DataTextField="Key" DataValueField="Value"> </telerik:RadComboBox> <asp:Button ID="btnGo" runat="server" Text="GO" OnClick="btnGo_OnClick" />

<telerik:RadGrid ID="radGrid1" runat="server" AutoGenerateColumns="false" AllowPaging="true" OnNeedDataSource="radGrid1_OnNeedDataSource"    OnItemCommand="radGrid1_ItemCommand" OnColumnCreated="radGrid1_OnColumnCreated"
    OnItemDataBound="radGrid1_OnItemDataBound">
    <MasterTableView AutoGenerateColumns="false" NoMasterRecordsText="<%$Resources:GlobalResource, noRecords%>">
        <Columns>
            <telerik:GridBoundColumn DataField="Id" UniqueName="Id" Visible="false">
            </telerik:GridBoundColumn>
            <telerik:GridBoundColumn DataField="UnitNumber" UniqueName="UnitNumber" Visible="false">
            </telerik:GridBoundColumn>
            <telerik:GridClientSelectColumn UniqueName="Selected">
            </telerik:GridClientSelectColumn>
        </Columns>
        <NestedViewSettings>
            <ParentTableRelation>
                <telerik:GridRelationFields DetailKeyField="Id" MasterKeyField="Id" />
            </ParentTableRelation>
        </NestedViewSettings>
        <NestedViewTemplate>
            <asp:Panel runat="server" Visible="false" ID="InnerContainer">
               <!-- Some code -->
            </asp:Panel>
        </NestedViewTemplate>
    </MasterTableView>
</telerik:RadGrid>