Set update parameter default value in code behind:
Formview
....
Meeting Time:
<asp:textbox ID="TimeTextBox" runat="server" Text='< %# Bind("Time") %>' />
...
<updateparameters>
<asp:parameter Name="Time" Type="String" />
<asp:parameter Name="Rid" Type="Int32" />
</updateparameters>
</asp:textbox>
Code behind
Protected Sub MemberDetailFV_ItemUpdating(ByVal sender As Object, ByVal_
e As System.Web.UI.WebControls.FormViewUpdateEventArgs)_
Handles MemberDetailFV.ItemUpdating_
MemberDetailDS.UpdateParameters("Time").DefaultValue = Now()
End Sub