第一个是判断对象是否创建，如Assigned(form1)，判断窗体是否创建
第二个是设置空，即null，去除引用
assign的用法和短语例句
就你所学的assign，你掌握了哪些用法，又掌握了哪些 短语 例句?以下是我给大家带来assign的用法和短语及参考例句，以供参阅。
assign的用法 assign的用法1：assign的基本意思是“分配,交给”,指把房屋、土地、工作任务等分配给某人,而非完成某工作而选择人,带有指令性或官方色彩,是及物动词,一般后接双宾语,其间接宾语可转化为介词to的宾语,有时间接宾语可以省略。
assign的用法2：assign也可作“指派,选派”解,指委派某人去做某事或分配某人到某岗位去工作,后常接动词不定式作宾语补足语或介词to引起的短语。
assign的用法3：assign还可作“指定,订出”解,指确定时间、地点、用途或说出原因、理由等,后接介词to或for,常用于被动结构中; 有时还可接as+ n. 充当补足语的复合宾语。
assign的常用短语 assign to (v.+prep.)
分配给give sb duties concerning sth
assign sth to sb
指定,选定provide
assign sb/sth to sth/sb
用于 be ～ed 结构
归因于belong to
assign sth to sth
用于 be ～ed 结构
确定fix (a time, place, reason, etc. for sth)
assign sth to sth
用于 be ～ed 结构
转让;让与give the ownership of rights or property to sb
assign sth to sb/sth
assign的用法例句 1. It had been a monumental blunder to give him the assign-ment.
当时把这项任务给他是大错特错了。
2. When teachers assign homework, students usually feel an obligation to do it.
当老师布置家庭作业的时候，学生们通常觉得做作业是分内之事。
3. It is possible to assign an exact date to this building.
这座建筑物的确切年代是可以确定的.
4. It's wise to assign special exercises to the weaker students.
给智能不足的学生指定专门的练习是个明智的 方法 .
5. Influenced by old ideas, some units assign posts according to seniority.
由于受旧观念的影响, 有些单位分配工作按资排辈.
6. It's difficult to assign any reason for the failure.
失败的原因很难确定.
7. When I taught, I would assign a topic to children which they would write about.
我教课时会给孩子们布置一个题目，让他们就这个题目写点东西。
8. Under Mr. Harel's system, each business must assign a value to each job.
根据哈雷尔先生的体系，每个企业必须赋予每份工作一定的价值。
9. The selling broker is then required to assign a portion of the commission to the buyer broker.
卖方经纪人须随后将部分佣金分给买方经纪人。
10. Assign the letters of the alphabet their numerical values ― A equals 1, B equals 2, etc.
给字母表里的每个字母赋予相应的数值――A等于1，B等于2，等等。
11. Later in the year, she'll assign them research papers.
今年晚些时候，她将给他们指定研究论文。
12. Assign a direction and a letter to each unknown current.
请对每个未知电流标以方向和字母记号.
13. The bankrupt must also assign all of his patents to the receiver.
破产人必须把他的所有专利权转给清算人.
14. Can we assign jealousy as the motive for the crime?
我们能否确定这一犯罪动机是出于嫉妒?
15. The doctors were unable assign a cause for her illness.
大夫们不能确定她的病因.
assigned的英语例句 1. He paid for and was assigned a cabin in first class.
他付完钱后被安排到了头等舱。
2. I was assigned to Troop A of the 10th Cavalry.
我被派往第10骑兵队的A连。
3. A patient going through acute detox will have an assigned nurse nearby.
接受急性脱瘾治疗的病人身边会有一名指派的护士看护。
4. Each of us was assigned a minder, someone who looked after us.
我们每个人都被派了一个看护人来照顾我们。
5. He assigned her all his land in Ireland.
他把自己在爱尔兰的所有土地都转给了她。
6. The two large classrooms have been assigned to us.
这两间大教室分配给了我们。
7. The sergeant assigned him to KP.
中士派他下伙房去帮厨。
8. The general assigned him to do the tough task.
将军派他去完成这项艰巨的任务.
9. A different policeman has been assigned to the case.
另一名警察被派去处理该案.
10. He was assigned to the company's branch in Cairo.
他被派到公司的开罗分部.
11. He assigned the students a few books to read.
他给学生指定了几本书要他们读.
12. The captain assigned two soldiers to guard the gate.
上尉派了两个士兵守大门.
13. The firm arranged that he should be assigned to the branch office.
公司安排他到分公司去工作.
14. Which room has been assigned for the committee meeting?
选定哪个房间开委员会会议?
15. She assigned her whole estate to a charitable organization.
