动态创建表达式 Expression<func<T,T>>

Question

请教一个问题，如果是 Expression<func<T,T>> 这样的表达式如何动态创建，
比如：Expression<Func<Customer, Customer>> exp = a => new Customer { name = "" };
想要根据条件动态赋值字段属性，结果类似这样：

if(addrParam!="")
  exp= a => new Customer { name = "",addr = addrParam};
if(telParam!="")
  exp= a => new Customer { name = "",addr = "",tel = telParam };

不是这种表达式：Expression<func<T,bool>>。
希望帮忙解答，谢谢！