Exception occured when map single object from EF Core entity class (with proxy) #1024

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1. DocSvartz commented on Oct 12, 2026

   

   DocSvartz

   on Oct 12, 2026

   Last edited by DocSvartz

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   Hi, @joko1189.
   This is expected behavior. Mapster always returns a mapping function for the types you request (or declared of members within the Type).

   The method .Adapt<CreateApiRequest>() in question is essentially a helper for in cases where the source type needs to be determined at runtime.

   Note

   .Adapt<CreateApiRequest>() is equal .Adapt<object,CreateApiRequest>() which is a meaningless operation, since an actual instance of type object cannot have state that could be passed during mapping 😅.

   For this reason, the specified method performs two actions simultaneously:

   1. Determines the actual (runtime) type of the source variable;
   2. Requests a mapping function from the actual (runtime) type to the Destination type.

   As i investigated, it turns out that entity type is Proxy rather than actual type (i'm using EF LazyLoadingProxies).

   You most likely set the following value somewhere in the configuration:
   TypeAdapterConfig.GlobalSettings.AllowImplicitSourceInheritance = false;

   default state is:
   TypeAdapterConfig.GlobalSettings.AllowImplicitSourceInheritance = true;

   For this reason, an automatically created proxy source type is prohibited inheriting configuration from its parent type, and you receive the error you mentioned.

   [TestMethod]
   public void ProxySourceTypeInheritanceBaseSourceSettings()
   {
       TypeAdapterConfig.GlobalSettings.RequireDestinationMemberSource = true;
       TypeAdapterConfig.GlobalSettings.AllowImplicitSourceInheritance = false; // comment or set to true 
   
   
       TypeAdapterConfig<SimplePoco, SimpleDto>
           .NewConfig()
           .Ignore(x => x.IgnoreData)
           .Compile();
   
       var proxy = new SimplePocoProxy() { Id = Guid.NewGuid(), Name = "Hello" };
   
       var result = proxy.Adapt<SimpleDto>(); // exception if  AllowImplicitSourceInheritance  = false; no exception  if AllowImplicitSourceInheritance  = true
   }
   
   

   public class SimplePocoProxy : SimplePoco
   {
   
   }