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POHow do I handle nested NPoco objects that may be null?
 

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  1. POHow do I handle nested NPoco objects that may be null?
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    <p>I am using NPoco for object mapping from my database. I have the following entities:</p> <pre><code>public abstract class NamedEntity { public int Id { get; set; } public string Name { get; set; } } public class Person : NamedEntity { public Office Office { get; set; } } public class Office : NamedEntity { public Address Address { get; set; } public Organisation ParentOrganisation { get; set; } } public class Address { public string AddressLine1 { get; set; } } public class Organisation : NamedEntity { } </code></pre> <p>and I am retrieving the objects using NPoco in my repository:</p> <pre><code>var people = Context.Fetch&lt;Person, Office, Address, Organisation&gt;(sql); </code></pre> <p>This is working fine, except for the case where a <code>Person</code> does not have an <code>Office</code>, in which case result of the <code>LEFT JOIN</code> in the sql query returns null for the Office, Address and Organisation columns.</p> <p>In this situation, an unhandled exception is thrown in NPoco:</p> <pre><code>System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---&gt; System.NullReferenceException: Object reference not set to an instance of an object. at poco_automapper(Person , Office , Address , Organisation ) --- End of inner exception stack trace --- at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor) at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments) at System.Delegate.DynamicInvokeImpl(Object[] args) at NPoco.MultiPocoFactory.CallCallback[TRet](Delegate callback, IDataReader dr, Int32 count) at NPoco.MultiPocoFactory.&lt;&gt;c__DisplayClassa`1.&lt;CreateMultiPocoFactory&gt;b__9(IDataReader reader, Delegate arg3) at NPoco.Database.&lt;Query&gt;d__14`1.MoveNext() </code></pre> <p>Is there a way to handle this situation? Or will I have to resort to a flattened object, or separate database calls?</p>
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    1. COHey, I'm the primary developer on NPoco. I wasn't actually aware that this scenario was supported. It will support having one class with nested classes, but they also can't have nested classes. If this indeed does work when there is office data can you please raise an issue on https://github.com/schotime/NPoco/issues and I will take a closer look.
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      1. POHow do I handle nested NPoco objects that may be null?
      1. USSchotime
    2. COSo was this functionality that _almost_ worked that you weren't aware of?
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