How to get all checked CheckBoxes in CheckBoxList control in ASP.Net

Dear Sir

I have a checkboxlist control in ASP.NET

                        <asp:CheckBoxList ID="chkchrges" runat="server">
                   
                       </asp:CheckBoxList>

I am binding in following way

  chkchrges.DataSource = objclsChargeMaster
            chkchrges.DataTextField = "chrgdcd"
            chkchrges.DataValueField = "chrgcd"
            chkchrges.DataBind()

And i am trying to get values (value member) of checked checkboxes

I am trying in folllowing way but each time it rerurns false on  

li.Selected

  For Each li As ListItem In chkchrges.Items
                    If (li.Selected) Then
                        Dim XX = li.Value
                        '' Do something with Value
                    End If
                Next

please help