Null Reference exception when using ICacheManager.... #472

7 Answer(s)

• 

  0

  hikalkan created 9 years ago

  Support Team

  Hi,

  Your code seems corrent. I think _CacheManager and brandCacheBySeo are not null. Can you check it? Also, please share your stack trace to understand which method throws this exception.

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  0

  theedge created 9 years ago

  Hi Halil,

  Yep both of those references are not NULL. Here is the call stack as requested:

  [NullReferenceException: Object reference not set to an instance of an object.]
     Abp.Runtime.Caching.CacheExtensions.GetOrDefault(ICache cache, TKey key) +53
     OzCruisingPlatform.Application.Services.Cache.OzCpCacheService.GetReferenceBrandBySeoFriendlyName(OzCpGetReferenceBrandBySeoFriendlyNameInput aParams) in D:\Data\TFS\Ozcruising\VS 2015\OzCruisingPlatform\OzCruisingPlatform.Application\Services\Cache\OzCpCacheService.cs:86
     Castle.Proxies.OzCpCacheServiceProxy.GetReferenceBrandBySeoFriendlyName_callback(OzCpGetReferenceBrandBySeoFriendlyNameInput aParams) +56
     Castle.Proxies.Invocations.IOzCpCacheService_GetReferenceBrandBySeoFriendlyName.InvokeMethodOnTarget() +179
     Castle.DynamicProxy.AbstractInvocation.Proceed() +110
     Castle.DynamicProxy.AbstractInvocation.Proceed() +447
     Abp.Domain.Uow.UnitOfWorkInterceptor.PerformSyncUow(IInvocation invocation, UnitOfWorkOptions options) +62
     Castle.DynamicProxy.AbstractInvocation.Proceed() +447
     Castle.DynamicProxy.AbstractInvocation.Proceed() +447
     Castle.DynamicProxy.AbstractInvocation.Proceed() +447
     Castle.Proxies.OzCpCacheServiceProxy.GetReferenceBrandBySeoFriendlyName(OzCpGetReferenceBrandBySeoFriendlyNameInput aParams) +255
     CruisesDesktop.Web.Controllers.CruisesController.ByBrand(String aBrandNameSeoFragment) in D:\Data\TFS\Ozcruising\VS 2015\CruisesDesktop\Cruises.Web\Controllers\CruisesController.cs:37
     lambda_method(Closure , ControllerBase , Object[] ) +141
     System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters) +228
     System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +34
     System.Web.Mvc.Async.AsyncControllerActionInvoker.<BeginInvokeSynchronousActionMethod>b__39(IAsyncResult asyncResult, ActionInvocation innerInvokeState) +38
  

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• 

  0

  theedge created 9 years ago

  Bump!!!

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  0

  hikalkan created 9 years ago

  Support Team

  Is your key null? aParams.BrandSeoFriendly? Because the code throws exception is very simple:

  public static TValue GetOrDefault<TKey, TValue>(this ICache cache, TKey key)
          {
              return (TValue)cache.GetOrDefault(key.ToString());
          }
  

  This code can throw an exception if cache or key is null.

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• 

  0

  theedge created 9 years ago

  Hi Halil,

  My key is not null as far as I am aware. My cache is empty and I am supplying a key value from my passed in value of aParams.BrandSeoFriendly which is the string "celebrity-cruises".

  So is it possible that if there is no value associated with the key that the hard cast of:

  (TValue)cache.GetOrDefault(key.ToString())
  

  is failing? Wouldn't soft cast of:

  cache.GetOrDefault(key.ToString()) as (TValue)
  

  be better? It seems to me that this issue is because the associated value is actually an INT.

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• 

  0

  hikalkan created 9 years ago

  Support Team

  Hi,

  I think this implementation is better: <a class="postlink" href="https://github.com/aspnetboilerplate/aspnetboilerplate/blob/master/src/Abp/Runtime/Caching/CacheExtensions.cs#L52">https://github.com/aspnetboilerplate/as ... ons.cs#L52</a>

  public static TValue GetOrDefault<TKey, TValue>(this ICache cache, TKey key)
          {
              var value = cache.GetOrDefault(key.ToString());
              if (value == null)
              {
                  return default(TValue);
              }
  
              return (TValue) value;
          }
  

  Will be released in next version.

  But note that: Do not store null values in the cache since MemoryCache does not allow null values.

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• 

  0

  theedge created 9 years ago

  Hi Halil,

  I am not storing NULL values in the cache. The exception is being thrown when their is no match in the cache. Not sure if it has to do with the fact that the value type of int can be NULL?

  For what it is worth I modified my code (unsing 0.7.4.1) to use Get() instead of GetOrDefault(), leaving everything else unchanged and the exception went away.

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