have to 用于现在完成时的例子并不少见。例如：
We have had to turn down four applicants already. 我们已经不得不回绝了四位申请人。
Not all companies have had to cut back on training. 不是所有公司都得削减培训费用。
Since his illness. He has had to swear off tennis. 他自从患病以来不得不停止打网球。
但是，进行时的不多见，网上也能查到一些例句，但是都没有权威性，还需要查查资料。