Question

c#中有一句 interest+=","+i.tostring();是什么意思

Answer 1

interest是个字符串变量
interest+=","+i.tostring()就是等同于
interest=interest+","+i.tostring()
比如interest值是"abc"，i的值是123，那这个语句让interest值变成了
abc,123
i.toString()是将i转换为字符串形式

Answer 2

就是字符串拼接
比如一开始
interest值是“test”
i是5
interest+=","+i.tostring();
结果
interest值为 “test，5”

Answer 3

首先interest应该是string类型
假设 interest=“AAA”,i=0,则
interest+=","+i.tostring();等价于 interest=interest+","+i.tostring();
运行后 interest=“AAA,0”