That is not strictly true for all states.
Some of the states have unbound delegates.
Yes, but I am pretty sure I am correct saying 1237 bound delegates will win it for him.
I was not trying to say all the delegates are bound, but only about 95 percent of them.
The states where Trump has won tend to be ones with bound delegates, because of the recent rule changes this cycle and the fact he tends to win where people vote rather than when the state party picks delegates in another way. From this detailed Washington Post explanation of the process way back in February (don't like Wash Post, but this was a good article):
The Republican National Committee recently enacted a new rule to increase the significance of bound delegates. According to the rule, states that have a "presidential preference poll" must bind their delegates to the outcome of the poll, meaning that most caucuses and primaries should result in bound delegate allocations. Some states, however, have chosen to circumvent the rule by altering their primary voting processes. For instance, in Colorado, Republican voters won't caucus directly for delegates to the national convention. Rather, they'll caucus for delegates to the state convention. Then, the state convention will choose delegates to send to the national convention.