C Sharp :: Delete Rows In Gridview

I am having a problem with deleting gridview rows. I am populating my gridview by selecting value in a dropdownlist then by clicking the add button, value will be added in my gridview, here is my code:

In my aspx:

<asp:GridView ID="GridView1" runat="server" 
                CssClass="mGrid" EmptyDataText = "There are no records to display">
                <Columns>
                    <asp:TemplateField ItemStyle-Width="10">
            <HeaderTemplate>  
            </HeaderTemplate>
            <ItemTemplate>
                <asp:CheckBox ID="CheckBox1" runat="server"/>
 
[Code] ....

With the btnRemove codes above, If I clicked it, it'll remove all values in my gridview even the unchecked rows, what I want is that just the checked rows not all. And are there any other simple way of removing rows in a gridview than using checkbox? I am using c# with asp.net.