补充一点语法分析：

I have heard of him / his getting married next month.（这里him / his getting married 为动名词的复合结构）

I have heard that he will get married next month.（很显然that从句为宾从）

还要注意：hear sb doing这个结构为复合结构，即doing用作宾补。

陈老师的解答很清晰，也很有说服力。其实，这个问题还可以拓展一下，hear of sb doing sth 用于否定句还可表示“拒绝（或不允许）某事”，通常与 will, would 连用。如：

I will not hear of you going. 我不会同意你去。

He would not hear of that being possible. 他不肯听人说那种事是可能的。

I offered to go but she wouldn’t hear of it. 我建议由我去，但她不允许。

He wouldn’t hear of Philip leaving them. 他不愿听到菲利浦离开他们。

They wouldn’t hear of us postponing the trip. 他们就是不同意我们推迟旅行。

At all events she would not hear of Jim leaving them. 不管怎样她不愿意让吉姆离开他们。

He would not hear of Mrs. Mackenzie and her daughter quitting the house. 他不肯听麦凯齐太太和她的女儿离家出走的事。

He won’t hear of his daughter becoming a police officer. He thinks it’s much too dangerous. 他绝不肯让女儿做警察，他觉得那行业太危险了。

1. hear of sb./sb.'s doing sth.表示“听说某人做某事”的例句：

I have never heard of his [him] having married the girl. （外语教学与研究出版社2006年10月第1版：《英语搭配大辞典》p.833）

2. will (would / could) not hear of 是一个固定用法，意思是“不同意”、“拒绝考虑”、“不允许”等。of 后面可以接名词、代词，也可以接“人称代词宾格或形容词性物主代词 + 动名词”结构。例如：

I won't hear of you [your] marrying him. （外语教学与研究出版社2006年10月第1版：《英语搭配大辞典》p.833） 

以下例句均出自英语原著：

I will not hear of you making a trip to that place. (EPV) 我绝不同意你到那个地方去旅游。

I want to go to the show tonight, but I know my mother will not hear of it. (DAI) 我想今晚去看演出，但我知道妈妈绝不会允许我去。

Mr. Creamer, her medical man, would not hear of her returning to her old haunts and dissipation in London. (EDECT) 她的医生克里默先生坚决反对她回到老地方去，坚决反对她回到伦敦的放荡生活中去。

（以上转引自赵振才编著的《英语常见问题解答大词典》增订版）