Checkbox value is always empty even if i check it

I made a button to delete files from a database, to delete a file you need to check a checkbox and then click a button. somewhy when i click the button and write the checkbox value to the html it always says false...

ASPX:

<asp:GridView HorizontalAlign="Center" ID="GridView1" runat="server" class="" AutoGenerateColumns="False" BackColor="White" BorderColor="#CCCCCC" BorderStyle="None" BorderWidth="1px" CellPadding="4" ForeColor="Black" GridLines="Horizontal" DataKeyNames="ID">
    <Columns>
        <asp:TemplateField HeaderText="Name">< ItemTemplate >
                            < asp:LinkButton ID = "LinkButton2" runat="server" OnClick="OpenDocument" Text='<%# Eval("File_Name") %>'></asp:LinkButton>
                        </ItemTemplate>
        </asp:TemplateField>
        <asp:TemplateField HeaderText="Delete?">< ItemTemplate >
                            < asp:CheckBox ID = "CheckBox1" runat="server" />
                        </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>
<asp:Button runat="server" Text="Update" ID="Update" class="button" OnClick="UpdateTable" Style="font-size: 20px" />

Code Behind:

protected void UpdateTable(object sender, EventArgs e)
{
    foreach (GridViewRow item in GridView1.Rows)
    {
        CheckBox chk = (CheckBox)item.FindControl("CheckBox1");
        if (chk != null)
        {
            //This is being written and always false
            Response.Write(chk.Checked);
            if (chk.Checked)
            {
               //Delete the item. (never being executed)
            }
        }
    }
}

I expected chk.Checked to be True since i've clicked it...