一、动态创建
ParameterExpression parameter = Expression.Parameter(typeof(User), "u"); //创建委托 MemberExpression member = Expression.PropertyOrField(parameter, "F_FullName"); //创建查询字段 ConstantExpression constant = Expression.Constant("张苏纳"); //变量赋值 var expression= Expression.Equal(member, constant); //创建匹配条件 var lambda = Expression.Lambda<Func<User, bool>>(expression, parameter); var list = dbcontext.Set<User>().Where(lambda);//创建完整查询条件