Some of our events would be called again e.g IntializeDataSource (WebGrid) or PrepareDataBinding (WebGrid). But You can also use 'If Not ISPostBack' to avoid some code inside those event to be called again. I think there no much different with the code you used on aspnet. You only need to customize so it can work as you expect.

Regards,
Handy

we have a big problem with the perfomance of our system and we have a risk in our project, i appreciate your help.

I want to explain how use to work before use the webcontrols.

for the dropdownlist and the gridwiew we have the normal methods in the form_load like this

  loadsupplier()

  loadinvoices()

so we load the dropdownlist and the gridviews only once in the page (when the page is load) and when ocurred other event the methods loadsupplier() and loadinvoices() are not reload.

I hope you have been understand the context above if you have any question let me know

But now using the webcontrols in the case of webgrid or webcombo we choose the datasource: isdatasource or objectdatasource and those controls get associate with a method that return the information.

The focus of the our problem is that we need to configurate the webcombos and webgrid only load once when the page load and then when we use a button event not reload the webcombos neither webgrids.

I hope you can understand our problem if you have any question please let me know, is really critical resolve this perfomance problem because in each button event all webcombos an webgrids are reolad and is so slow. i hope your soon answer.

Sorry for the late reply. May i know what button you used? Does it trigger FullPostBack?

Normally, we bind data into WebGrid and WebCombo inside IntializeDataSource event, not Page_Load. If your Button do FullPostback, of of course InitializeDataSource and Page_Load event would be called again. 
That's happen also for FlyPostBack condition (InitializeDataSource event).
e.g for refresh.

May i know why do you need them to be called once?

Regards,
Handy