Assembly: Microsoft.Xna.Framework (in microsoft.xna.framework.dll)
An application sets one active pass (within one active technique) in the effect system by calling Begin. An application signals the end of the active pass by calling End. Begin and End must occur in a matching pair, within a matching pair of Effect.Begin and Effect.End calls.
If the application changes any effect state using any of the Effect methods inside of a Begin/End matching pair, the application must call CommitChanges to set the update the device with the state changes. If no state changes occur within a Begin and End matching pair, it is not necessary to call CommitChanges.