System.Web.HttpException: The control collection cannot be modified during DataBind, Init, Load, PreRender or Unload phases. at System.Web.UI.ControlCollection.RemoveAt(Int32 index) at System.Web.UI.Control.AddedControl(Control control, Int32 index) at MasterPage_FirstPage.PositionAdd(String Position, PlaceHolder Obj) at MasterPage_FirstPage.SelectModual(Int32 BoxID, String Modules, String BorderID, String Title, String Position, String C_Befor, String C_After, String D1, String D2, String D3, String D4, String D5, String D6, String D7, String D8, String D9, String D10, Boolean cash) at MasterPage_FirstPage.Start()