Does a defendant have to prove a burglary can be proven where the required intent was formed after the crime was committed?

Defendant cites People v. Graham (1958) 156 Cal.App.2d 525, 319 P.2d 677, as an example supporting his contention burglary cannot be proved where the required intent arises after the entry into a building. In that case the court found burglary had not been established because the intent to steal appeared to have been formed after the entry. The problem in Graham, however, was not with the time at which the intent arose but rather that the prosecution charged entry with the intent to steal but the evidence established entry was made with the intent to rape, and the intent to steal arose after the entry. The prosecution simply failed to prove the charged crime. (Id. at pp. 528-529, 319 P.2d 677.)