KeyNotFoundException: The given key 'Id' was not present in the dictionary.

[LucasWBritz]

Hi!
I'm getting this error randomly when I try to query data from our database using dapper and then convert the result to an object using Slapper.

Code sample:

var data = await _dapperRepository.QueryAsync<dynamic>(sqlQuery, parameters);
var result = Slapper.AutoMapper.MapDynamic<UserData>(data).ToList();

The exception:
System.Collections.Generic.KeyNotFoundException: The given key 'Id' was not present in the dictionary.   at System.Collections.Generic.Dictionary`2.get_Item(TKey key)   at System.Linq.Enumerable.SelectListIterator`2.ToArray()   at System.Linq.Enumerable.DefaultIfEmptyIterator`1.ToArray()   at Slapper.AutoMapper.InternalHelpers.GetCacheKey(Type type, IDictionary`2 properties, Object parentInstance)   at Slapper.AutoMapper.InternalHelpers.GetInstance(Type type, IDictionary`2 properties, Object parentInstance)   at Slapper.AutoMapper.InternalHelpers.MapCollection(Type type, IDictionary`2 dictionary, Object instance, Object parentInstance)   at Slapper.AutoMapper.InternalHelpers.Map(IDictionary`2 dictionary, Object instance, Object parentInstance)   at Slapper.AutoMapper.Map(Type type, IEnumerable`1 listOfProperties, Boolean keepCache)   at Slapper.AutoMapper.MapDynamic[T](IEnumerable`1 dynamicListOfProperties, Boolean keepCache) 

This error is happening inside this method when trying to Select(id => properties[id]). The Key does not exist in the dictionary and is throwing this exception.

private static InstanceKey GetCacheKey(Type type, IDictionary<string, object> properties, object parentInstance)
  {
        var identifierValues = GetIdentifiers(type)?.Select(id => properties[id]).DefaultIfEmpty(Guid.NewGuid()).ToArray()
         ?? new object[] { Guid.NewGuid() };

         var key = new InstanceKey(type, identifierValues, parentInstance);
         return key;
  }

Unfortunately I'm not able to reproduce the error locally and submit a pull request because it happens randomly in our production environment. Never had this issue running locally and debugging.

Does anyone have an idea on what could be the cause of the error?

Thank you!

[alxtr1bal]

Same here... unable to pinpoint this problem though...

[povillar1985]

got same issue. any updates here? Thanks

[randyburden]

Someone would need to create a test that reliably reproduces the problem in order for anyone to attempt to address this issue.

[CrisConter]

Hi! I was reading this topic, because I had the same problem here. I just set a unique identifier and it work very well.
Like this:
Slapper.AutoMapper.Configuration.AddIdentifier(typeof(MyClass), "MyUniqueIdentifier");

I hope it helps

[elAndyG]

any chance of this getting updated? The PR above seems like a good fix.