Sending message including values from checkboxes

I have manage to send a simple message but also I want to include values from checkboxes and don't know how to do that.
Here is the code in Default.aspx:
<asp:CheckBoxList ID="chklstStates" runat="server"> <asp:ListItem Text="Option 1" Value="Option 1"></asp:ListItem> <asp:ListItem Text="Option 2" Value="Option 2"></asp:ListItem> <asp:ListItem Text="Option 3" Value="Option 3"></asp:ListItem> </asp:CheckBoxList> <asp:Label ID="lblName" runat="server" Text="Name"></asp:Label><br /> <asp:TextBox ID="txtName" runat="server"></asp:TextBox><br /> <asp:Label ID="lblMail" runat="server" Text="Email"></asp:Label><br /> <asp:TextBox ID="txtMail" runat="serv ...