("{\"CreatedAt\":\"2015-08-02T18:29:24.9869395+00:00\",\"ProjectId\":80456868}"));
```
I take it from that code that the task that would be created would be of type `ITask`, which of course will not be correct as that is an interface type with no parameters (just a marker interface)
Looking in `Hangfire.Job` SQL job table I see, in InvocationData:
```
{"Type":"Blueprint.Core.Tasks.ImmediateTaskExecutor, Blueprint.Core, Version=3.6.7.0, Culture=neutral, PublicKeyToken=null","Method":"Execute","ParameterTypes":"[\"Blueprint.Core.Tasks.ITask, Blueprint.Core, Version=3.6.7.0, Culture=neutral, PublicKeyToken=null\"]","Arguments":"[\"{\\\"CreatedAt\\\":\\\"2015-08-02T18:29:24.9869395+00:00\\\",\\\"ProjectId\\\":80456868}\"]"}
```
---
### Author:  [@AdamBarclay](https://discuss.hangfire.io/u/AdamBarclay)
#### Post date: [August 3, 2015, 4:08pm UTC](https://discuss.hangfire.io/t/argument-as-interface-types/1189/4 "2015-08-03T16:08:00Z")
I have created an example that shows the problem I am running in to, based off of the minimal Hangfire sample console app:
> **[Dropbox - Error](https://www.dropbox.com/s/5xakav9lkbbibao/Hangfire%20Interface%20Argument%20Bug%20Example.zip?dl=0)**
>
> Dropbox is a free service that lets you bring your photos, docs, and videos anywhere and share them easily. Never email yourself a file again!
Hopefully that shows the problem better than just a text description
---
### Author:  [@odinserj](https://discuss.hangfire.io/u/odinserj)
#### Post date: [August 4, 2015, 2:23pm UTC](https://discuss.hangfire.io/t/argument-as-interface-types/1189/5 "2015-08-04T14:23:35Z")
@AdamBarclay, serialized string of a job argument does not include the type name by default, and thus it can’t be deserialized. However, you can change this by passing your own serialization options:
```auto
JobHelper.SetSerializerSettings(
new JsonSerializerSettings { TypeNameHandling = TypeNameHandling.All });
```
This will enable [Json.NET](http://Json.NET) to serialize your arguments with preserving the type information. Please try this.
---
### Author:  [@AdamBarclay](https://discuss.hangfire.io/u/AdamBarclay)
#### Post date: [August 4, 2015, 2:41pm UTC](https://discuss.hangfire.io/t/argument-as-interface-types/1189/6 "2015-08-04T14:41:48Z")
@odinserj, I’ve just tried that but it results in an exception when the job is being run:
Newtonsoft.Json.JsonSerializationException
Type specified in JSON ‘System.Linq.Enumerable+WhereSelectArrayIterator`2[[System.Reflection.ParameterInfo, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.Type, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]], System.Core, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089’ is not compatible with ‘System.Type[], mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089’. Path ‘$type’, line 1, position 142.
at Newtonsoft.Json.JsonConvert.DeserializeObject[T](String value, JsonSerializerSettings settings)
at Hangfire.Common.JobHelper.FromJson[T](String value)
at Hangfire.Storage.InvocationData.Deserialize()
The `Arguments` column in `Job` table now contains:
```
{"$type":"System.String[], mscorlib","$values":["{\"$type\":\"Hangfire.ConsoleApplication.GreetingTask, Hangfire.ConsoleApplication\",\"Greeting\":\"Hello world\"}"]}
```
---
### Author:  [@odinserj](https://discuss.hangfire.io/u/odinserj)
#### Post date: [August 4, 2015, 2:47pm UTC](https://discuss.hangfire.io/t/argument-as-interface-types/1189/7 "2015-08-04T14:47:21Z")
@AdamBarclay, what Hangfire version are you using? [This PR](https://github.com/HangfireIO/Hangfire/pull/363) attempts to fix this in 1.4.3.
---
### Author:  [@AdamBarclay](https://discuss.hangfire.io/u/AdamBarclay)
#### Post date: [August 4, 2015, 2:52pm UTC](https://discuss.hangfire.io/t/argument-as-interface-types/1189/8 "2015-08-04T14:52:02Z")
@odinserj I was using version 1.4.1 (the default version from Hangfire.Sample github, which I had assumed was the latest version).
Having upgraded to 1.4.5 that now fixes the exception posted. Perhaps the default should be to include the type names in the JSON being serialised? It pushes Hangfire a step further towards ‘just working’ without requiring any extra configuration. I don’t think my usage is particularly abnormal.
Or at a minimum perhaps somewhere in the documentation?
Many thanks for all your work! Looking forward to replacing our home-grown solution with something that actually works real nice 😄
---
### Author:  [@odinserj](https://discuss.hangfire.io/u/odinserj)
#### Post date: [August 4, 2015, 3:06pm UTC](https://discuss.hangfire.io/t/argument-as-interface-types/1189/9 "2015-08-04T15:06:16Z")
> [@AdamBarclay](#):
>
> Perhaps the default should be to include the type names in the JSON being serialised? It pushes Hangfire a step further towards ‘just working’ without requiring any extra configuration. I don’t think my usage is particularly abnormal.
This is a breaking change, since objects serialized without `TypeNameHandling.All` should be de-serialized without this setting either. Need to think how to handle this.
---
### Author:  [@odinserj](https://discuss.hangfire.io/u/odinserj)
#### Post date: [August 5, 2015, 1:10pm UTC](https://discuss.hangfire.io/t/argument-as-interface-types/1189/10 "2015-08-05T13:10:53Z")
I moved 2 posts to a new topic: [Use `TypeNameHandling.All` when serializing arguments by default](https://discuss.hangfire.io/t/use-typenamehandling-all-when-serializing-arguments-by-default/1200)
---
### Author:  [@odinserj](https://discuss.hangfire.io/u/odinserj)
#### Post date: [August 5, 2015, 1:11pm UTC](https://discuss.hangfire.io/t/argument-as-interface-types/1189/11 "2015-08-05T13:11:16Z")