check box checked value get on button click

Question

check box inside data list and data list bind from database.

first i checked check box than select quantity from  drop_quantity and than click button submit data...

i want when click on button get value of check box and there quantity  

 

 

<asp:DataList ID="divProducts" Style="margin-top: 10px;" RepeatColumns="3" RepeatDirection="Horizontal"

runat="server">

<ItemTemplate>

<table>

<tr>

<td>

<div runat="server" style="width: 260px; height: 305px; margin-right: 10px; margin-bottom: 5px;

border: 6px solid #e6e6e6;">

<asp:Label ID="lbl_product_id" runat="server" Visible="false" Text='<%#Eval("ProductId") %>'></asp:Label>

<img style="height: 260px; width: 260px; object-fit: cover;" src='Products/<%#Eval("Image1") %>'

alt="image1" />

<asp:CheckBox ID="chkbox" runat="server" Style="margin-top: 5px; float: left; left: 10px;

text-decoration: none !important;" AutoPostBack="true" />

<h1 style="font-size: 14px; margin-top: 2px; font-family: myriad_mmregular; font-weight: normal;">

<a style="margin-top: 5px; text-decoration: none !important;" title='<%#Eval("ProductCode") %>&nbsp;<%#Eval("ProductName") %>'>

<b>

<asp:Label ID="Label1" runat="server" Text='<%#Eval("ProductCode") %>'></asp:Label>

</b>

<asp:Label ID="lbl_productName" runat="server" Text='<%#Eval("ProductName").ToString().Length > 20 ? Eval("ProductName").ToString().Substring(0, 20)+"..." : Eval("ProductName")%>'></asp:Label>

</a>

</h1>

<h1 style="margin-left: 150px;">

Quantity :</h1>

<span style="float: right; margin-right: 5px; margin-top: -30px;"><b class="prc"

style="font-size: 13px;">

<asp:DropDownList ID="drop_quantity" runat="server" AutoPostBack="true" Style="position: relative;

float: left; text-decoration: none !important; height: 22px; width: 40px;">

</asp:DropDownList>

</b></span>

<asp:Label ID="lbl_pro_nm" runat="server" Visible="false" Text='<%#Eval("ProName") %>'></asp:Label>

</div>

</td>

</tr>

</table>

</ItemTemplate>

</asp:DataList>

 

 

<asp:ImageButton ID="sbmt_btn" ImageUrl="images/submit1.jpg" runat="server"

OnClick="sbmt_btn_Click1" Style="margin-left: 695px; margin-top: -32px;" />