RadRibbonBar Button Click And RadGrid

[July]

Hello!
I have a RadRibbonBar in Master Page, and RadGrid in Details.
RadGrid contains

  <telerik:GridTemplateColumn  UniqueName="Select" HeaderStyle-Width="3%"  AllowFiltering="false">
                          
                          <ItemTemplate>
                           <asp:CheckBox  id="chkSelect" runat="server"  />
                          </ItemTemplate>
                          
                       </telerik:GridTemplateColumn>

When user click on Export button, I need Get all rows selected in RadGrid. And export to XLS.

I dont kwon how access to selected Rows from radribbonBar :-)

thanks!

july