PageState: You can use PageState much like you use ViewState

gistfile1.cs

SomeClass SomePoperty
{
    get 
    { 
        return PageState["SOME_PROPERTY_NAME"] ?? 
            (PageState["SOME_PROPERTY_NAME"] = default(SomeClass)) as SomeClass; 
    }
 
    set 
    { 
        PageState["SOME_PROPERTY_NAME"] = value; 
    }
}