if you placed datalist command buttons as -

<asp:DataList ID="DataList1" DataKeyField="CommentId" runat="server"
OnItemCommand="DataList1_ItemCommand">
<ItemTemplate>
<asp:LinkButton ID="Edit" Text="Select" CommandName="Edit" runat="server" />
<asp:LinkButton ID="delete" Text="Approve" CommandName="Delete" runat="server" />
.......

we all know well that the DataGrid is used for database work.we
can use DataGrid contorl to show data from database tables.
but it's that the new version of the DataGrid control in the c#
language and Vb.net is able to show any other objects
of classes which implements IList interface.

normally we define connectionstrings under
<connectionStrings> tag in the web.config
file.membership providers use that
connectionstring.what if we needed to use
the connectionstring in asp.net pages?.

sometimes it's needed to check whether there are multiple same
modules in the current page or not to keep one version of the
module or some other checks.

if you have a asp.net web page which is derived
from a master page then you may have trouble
using a form inside your page.It happens because
of your master page using a form.It's a little tricky
to be able to use another form which you need to use.
you have to use a javascript line for that.