Fan Xian asked if the Crown Prince knew about the assassination.

Fan Xian asked if the Crown Prince knew about the assassination, but he didn't mention it. Therefore, I don't know if Fan Xian asked if the Crown Prince knew about the assassination.

The specific content and purpose of Fan Xian's question to the Crown Prince was not clearly mentioned. Therefore, based on the information provided, I am unable to answer this question.

Yes, in the novel " Celebrating Years," the Crown Prince knew that Fan Xian was a prince. In chapter 239 of the novel, the Qing Emperor asked Fan Xian and the Crown Prince to meet Lin Ruofu. In their conversation, the Crown Prince unintentionally revealed the truth that Fan Xian was a Prince.

Fan Xian knew the truth behind the Niulan Street assassination. In " Celebrating Years," the masterminds behind the assassination of Fan Xian on Niulan Street were the Second Prince, the Eldest Princess, and Lin Gong. Lin Gong was the one who controlled Cheng Jushu. He had smuggled Cheng Jushu into the capital. The Second Prince did not want Fan Xian to take charge of the palace treasury, so he wanted to assassinate Fan Xian. The Eldest Princess seemed to support the Crown Prince, but in fact, she supported the Second Prince, so she also participated in the arrangements for the Niulan Street assassination. Fan Xian had learned this information while investigating the real culprit behind the scenes.

There was a complicated relationship between Fan Xian and Crown Prince Li Chengqian. The Crown Prince had tried to rope Fan Xian in for his use, but he did not know that the Empress and Eldest Princess had once planned to assassinate Fan Xian. The power behind the Crown Prince and the power behind Fan Xian had clashed twice. Once in Danzhou, Fan Xian was poisoned, and once in Niulan Street, Fan Xian was assassinated by an assassin. The conflict between Fan Xian and the Crown Prince continued to escalate. They tried to rope in each other's support. The Crown Prince had tried to lure Chen Pingping out to deal with Fan Xian, and Fan Xian had attacked the Crown Prince by exposing the Eldest Princess 'collusion with Northern Qi. In the end, the Crown Prince and the Second Prince's rebellion failed. Fan Xian assassinated the Qing Emperor and supported the Third Prince to ascend the throne. He lived in seclusion in Jiangnan.

Fan Xian was not the Crown Prince. The Crown Prince was the Qing Emperor's legitimate son, while Fan Xian was the illegitimate child of the Qing Emperor and Ye Qingmei. The Crown Prince's ability was considered the worst, and the Qing Emperor thought highly of Fan Xian. He even allowed him not to kneel. The Qing Emperor's attitude and attention toward the Crown Prince and Fan Xian were different. This also attracted the attention of everyone in court. Therefore, according to the information provided, Fan Xian was not the Crown Prince.

The Crown Prince and Fan Xian were two characters in " Celebrating Years." The Crown Prince was the Qing Emperor's son, while Fan Xian was the illegitimate child of the Qing Emperor and Ye Qingmei. In the scene where the Crown Prince personally went to the Inspection Court to save Si Lili, Chen Pingping's appearance reversed the situation and displayed his authority and power. Fan Xian was a transmigrator from the same era as Ye Qingmei. He had the soul of a modern person and a carefree personality, so it was easy for the audience to feel a sense of immersion. In the second season, Fan Xian would experience the process of self-awakening and finding his true self, growing from a chess piece to a chess player. Overall, the Crown Prince and Fan Xian were important characters in " Celebrating Years." Their development and interaction in the play would add more tension and plot to the story.

There was a complicated relationship between Fan Xian and Crown Prince Li Chengqian. The Crown Prince had tried to rope Fan Xian in for his use, but he did not know that the Empress and Eldest Princess had once planned to assassinate Fan Xian. The conflict between Fan Xian and the Crown Prince continued to escalate. They tried to rope in each other's support. The Crown Prince had tried to lure Chen Pingping out to deal with Fan Xian, and Fan Xian had attacked the Crown Prince by exposing the Eldest Princess 'collusion with Northern Qi. In the end, the Crown Prince and the Second Prince's rebellion failed. Fan Xian assassinated the Qing Emperor and supported the Third Prince to ascend the throne. He lived in seclusion in Jiangnan. Regarding the specific relationship between Fan Xian and the Crown Prince and the details of their battle, the search results did not provide a clear answer.

There was a complicated relationship between Fan Xian and the Crown Prince. The Crown Prince was a scheming person who was good at playing with people's hearts. His goal was to become the Emperor. The Crown Prince had a bad heart. In order to achieve his goal, he did not hesitate to sacrifice the people. The Crown Prince became interested in Fan Xian and tried to rope him in for his own use. However, Fan Xian was not easily detected by the Crown Prince. His attention shifted more to the Second Prince. With the Qing Emperor's support, Fan Xian gradually revealed the Crown Prince's secret and finally knocked the Crown Prince down to dust. Regarding the specific details of Fan Xian and the Crown Prince, the relevant information did not mention them.

There was a complicated relationship between Fan Xian and Crown Prince Li Chengqian. The Crown Prince had tried to rope Fan Xian in for his use, but he did not know that the Empress and Eldest Princess had once planned to assassinate Fan Xian. The power behind the Crown Prince and the power behind Fan Xian had clashed twice. Once in Danzhou, Fan Xian was poisoned, and once in Niulan Street, Fan Xian was assassinated by an assassin. The conflict between Fan Xian and the Crown Prince continued to escalate. They tried to rope in each other's support. The Crown Prince had tried to lure Chen Pingping out to deal with Fan Xian, and Fan Xian had attacked the Crown Prince by exposing the Eldest Princess 'collusion with Northern Qi. In the end, the Crown Prince and the Second Prince's rebellion failed. Fan Xian assassinated the Qing Emperor and supported the Third Prince to ascend the throne. He lived in seclusion in Jiangnan.