<ItemTemplate>
<asp:LinkButton ID="Edit" Text="Edit" CommandName="Edit" Font-Size="9" runat="server" />
<asp:LinkButton ID="delete" Text="Delete" CommandName="Delete" Font-Size="9" runat="server" />
</div>

<div class="ViewMain">
<div class="commentdiv" style="float:left;"><asp:TextBox ID="Comments"
Enabled="false" runat="server" Text='<%# Bind("Comment")%>' ></asp:TextBox></div>
</div>
</ItemTemplate>
<EditItemTemplate>
<div style=" margin-left:110px;">
<asp:LinkButton ID="Button1" runat="server" Font-Size="9" CommandName="Update" Text="Update" />
<asp:LinkButton ID="Button2" runat="server" Font-Size="9" CommandName="Cancel" Text="Cancel" />
</div>

<div id="ViewMain">
<div class="commentdiv" style="float:left;"><asp:TextBox ID="Comments" Enabled="true"
runat="server" Text='<%# Bind("Comment")%>' ></asp:TextBox></div>
</div>
</EditItemTemplate>

define command event handlers in code behind file -

protected void DataList1_EditCommand(object source, DataListCommandEventArgs e)
{
//call edit item template for selected index
DataList1.EditItemIndex = e.Item.ItemIndex;
bindgrid();//it will populate datalist again
}
protected void DataList1_DeleteCommand(object source, DataListCommandEventArgs e)
{
int deleteid = Convert.ToInt32(DataList1.DataKeys[e.Item.ItemIndex]);
MS_Comments_Controller control = new MS_Comments_Controller();
control.MS_Comments_DeleteComment(deleteid, ModuleId);
//all chlid datalist items must be deleted
DataList1.EditItemIndex = -1;
bindgrid();//it will populate datalist again
}
protected void DataList1_UpdateCommand(object source, DataListCommandEventArgs e)
{
Int32 cid;
String comment;
cid = Convert.ToInt32(DataList1.DataKeys[e.Item.ItemIndex]);
comment = ((TextBox)(e.Item.FindControl("Comments"))).Text;

MS_Comments_Controller control = new MS_Comments_Controller();
control.MS_Comments_UpdateComment(cid, comment, ModuleId);
DataList1.EditItemIndex = -1; //without it not works
bindgrid();//it will populate datalist again
}
protected void DataList1_CancelCommand(object source, DataListCommandEventArgs e)
{
DataList1.EditItemIndex = -1;//Call Item Template //without it not works
bindgrid();//it will populate datalist again
}