<myprefix:AccountFavorites runat="server" id="TheAccountFavorites" />
In your page set the info...
protected void Page_Load(object sender, EventArgs e)
{
TheAccountFavorites.TheAccountData=MyAccountData;//assuming you'll load up MyAccountData
}
In your control, expose AccountData as a public property. This will allow you to access it from the page.
public AccountData TheAccountData {get;set;}
This is assuming AccountData
was the type name and not something else, like a string. But you can change AccountData to string and it will work.