"可空对象必须具有值QUOT;非原始/非结构对象上检查空后异常

我收到可空对象必须检查空常规对象后有一个值，空检查后。我发现各种问题，主要是对LINQ到SQL，有相同的问题，但始终为空的基本类型（如布尔？或日期时间）

I'm getting Nullable object must have a value after checking for null on a regular object, after a null check. I've found various questions, mostly regarding linq-to-sql, having the same problem but always with nullable primitive types (as in bool? or DateTime?).

引起我的情况异常的行看起来是这样的：

The line causing the exception in my case looks like this:

myDataContext.Orders.Where(y => customer.Address == null || (string.IsNullOrEmpty(customer.Address.Street) || y.Customers.Addresses.Street == customer.Address.Street)))

客户类看起来是这样的：

public class Customer
{
    private Address address = null;
    public Address Address{get{return address;} set{address=value;}}
}

地址属性看起来是这样的：

address property looks like this:

public class Address
{
    private string street = null;
    public string Street{get{return street ;} set{street =value;}}
}

如果我更换上面这行代码：

If I replace above code line with this:

string custStreet = null;
if (customer.Address != null)
{
    custStreet = customer.Address.Street;
}

myDataContext.Orders.Where(y =>(customer.Address == null || (string.IsNullOrEmpty(custStreet) || y.Customers.Addresses.Street == custStreet)))

运行良好。我不已了解其中的原因。我也不想执行拉姆达语句本身之前定义的变量无数

it runs fine. I don't undestand the reason for that. I also don't want to define countless variables before executing the Lambda statement itself.

也请注意，上面LAMBDA语句是一个更大的拉姆达的一部分包含了几个这样的声明凡条款。我知道我可以用表达​​式树工作，但已经远编码这个，我真的不希望立即切换。

Please also note that above Lambda statement is part of a much bigger Lambda Where clause that contains a few more of such statements. I know I could work with Expression Trees but having coded this far, I really don't want to switch now.

修改

作为问题得到回答，我会告诉你我是如何工作的周围：我自己建一个递归的属性初始化。这不是一个字符串列表/数组或一个原始类型一切都抛出对激活类。我从的想法在这里并做了一些修改它（基本上忽略不需要初始化一切和而不是 Activator.CreateInstance（Type.GetType（property.PropertyType.Name））; 我用 Activator.CreateInstance（property.PropertyType））; 我甚至不知道，如果在原来的问题使用的版本会工作或者为什么有人想使用它。）

as the question was answered, I'm going to tell you how I worked around it: I build myself a recursive property initializer. Everything that is not a string, a list/array or a primitive type is thrown against the Activator class. I got the idea from here and made a few changes to it (basically, ignore everything that doesn't need to be initialized and instead of Activator.CreateInstance(Type.GetType(property.PropertyType.Name)); I used Activator.CreateInstance(property.PropertyType)); I'm not even sure if the version used in the original question would work or why anyone would want to use it.)