Question

I have a Grid View, I want to update all the rows that will be selected by checking the checkbook. First I want all the selected rows into a list. I don know how to do it. I know how to populate a grid from a list.
my grid view is

<asp:GridView runat="server" ID="GridForResult" 
        Visible="true" 
        ShowHeader="false"
        AutoGenerateColumns="false">
    <Columns>
        <asp:TemplateField ItemStyle-Width="120px" ItemStyle-Height="22px">
            <ItemTemplate>
                <%#Eval( "TestRoll")%>
            </ItemTemplate>
        </asp:TemplateField>
        <asp:TemplateField ItemStyle-Width="150px" ItemStyle-Height="22px">
            <ItemTemplate>
                <%#Eval( "Name")%>
            </ItemTemplate>
        </asp:TemplateField>
        <asp:TemplateField ItemStyle-Width="80px" ItemStyle-Height="22px">
            <ItemTemplate>
                <%#Eval( "Program")%>
            </ItemTemplate>
        </asp:TemplateField>
        <asp:TemplateField ItemStyle-Width="80px" ItemStyle-Height="22px">
            <ItemTemplate>
                <asp:CheckBox ID="chkSelected" runat="server" Text="Selected" />
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

My another problem is How to get only the selected (checkboxes) rows from the gridview?

Answer 1

Its pretty straight forward if you are not paging your grid and you want to maintain checked value on PostBack.
On GridView Markup, set DataKeyNames="{your primary key}"

Code – behind

List<string> primaryKeys = new List<string>();
foreach(GridViewRow row in GridForResult.Rows)
{
    CheckBox check = row.FindControl("chkSelected") as CheckBox;
    if(check.Checked)
    {
        primaryKeys.Add(GridForResult.DataKeys[row.RowIndex].Value.ToString());
    }
}

The List<string> primaryKeys will now hold all the checked primary keys.