Failed to load viewstate. The control tree into which viewstate is being loaded
I just added EnableViewState="false"
to my page placeholder and its gone. Hope it works for u as well.
What is important when you are adding controls dynamically is on which event you are adding them.
If you added controls on events that occur after load, they will be part of the viewstate you send to the client.
You will have to add those controls again before LoadViewState
is called.
If you run into cases where the decision of which controls to add is itself stored in the ViewState
or the value of a control, then remember even before the ViewState
is loaded, this data is available in Request.Params
Refer the asp.net page life cycle