Unidentifiable problem in List<> Serialization/Deserialization

The error being recieved:

Code (CSharp):

1. ArgumentNullException: Argument cannot be null.
2. Parameter name: elementType
3. System.Array.CreateInstance (System.Type elementType, System.Int32[] lengths) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System/Array.cs:640)
4. System.Array.CreateInstance (System.Type elementType, Int32 length) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System/Array.cs:620)
5. System.Xml.Serialization.XmlSerializationReaderInterpreter.ReadListString (System.Xml.Serialization.XmlTypeMapping typeMap, System.String values)
6. System.Xml.Serialization.XmlSerializationReaderInterpreter.GetValueFromXmlString (System.String value, System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlTypeMapping typeMap)
7. System.Xml.Serialization.XmlSerializationReaderInterpreter.ReadAttributeMembers (System.Xml.Serialization.ClassMap map, System.Object ob, Boolean isValueList)
8. System.Xml.Serialization.XmlSerializationReaderInterpreter.ReadMembers (System.Xml.Serialization.ClassMap map, System.Object ob, Boolean isValueList, Boolean readByOrder)
9. System.Xml.Serialization.XmlSerializationReaderInterpreter.ReadClassInstanceMembers (System.Xml.Serialization.XmlTypeMapping typeMap, System.Object ob)
10. System.Xml.Serialization.XmlSerializationReaderInterpreter.ReadClassInstance (System.Xml.Serialization.XmlTypeMapping typeMap, Boolean isNullable, Boolean checkType)
11. System.Xml.Serialization.XmlSerializationReaderInterpreter.ReadObject (System.Xml.Serialization.XmlTypeMapping typeMap, Boolean isNullable, Boolean checkType)
12. System.Xml.Serialization.XmlSerializationReaderInterpreter.ReadObjectElement (System.Xml.Serialization.XmlTypeMapElementInfo elem)
13. System.Xml.Serialization.XmlSerializationReaderInterpreter.ReadMembers (System.Xml.Serialization.ClassMap map, System.Object ob, Boolean isValueList, Boolean readByOrder)
14. System.Xml.Serialization.XmlSerializationReaderInterpreter.ReadClassInstanceMembers (System.Xml.Serialization.XmlTypeMapping typeMap, System.Object ob)
15. System.Xml.Serialization.XmlSerializationReaderInterpreter.ReadClassInstance (System.Xml.Serialization.XmlTypeMapping typeMap, Boolean isNullable, Boolean checkType)
16. System.Xml.Serialization.XmlSerializationReaderInterpreter.ReadObject (System.Xml.Serialization.XmlTypeMapping typeMap, Boolean isNullable, Boolean checkType)
17. System.Xml.Serialization.XmlSerializationReaderInterpreter.ReadRoot (System.Xml.Serialization.XmlTypeMapping rootMap)
18. System.Xml.Serialization.XmlSerializationReaderInterpreter.ReadRoot ()
19. System.Xml.Serialization.XmlSerializer.Deserialize (System.Xml.Serialization.XmlSerializationReader reader)

I have used the same code template for 2 different (currently working) data file scripts (one using ints, floats and strings for player data. Another using string arrays and int arrays for inventory/equipment data.). However I have ran into a problem when attempting to serialize a List<>, more specifically when attempting to deserialize and load.

Here are the pertinent pieces of said script:

The Save() Function, which to my knowledge is working 100% as intended and is creating the proper file

Code (CSharp):

1.     #region Save File
2.     public void Save()
3.     {
4. //Here I am fetching a static object who's children are the focus of our data serialization
5.         var blockObjects = transform.GetComponentsInChildren<WorldBlockData>();
6.  
7. //Run this code for as many children the manager contains
8.         for ( int i = 0; i < transform.childCount; i++) {
9.  
10. //Add the ID of the target object(s) to the data            
11.  
12. fileData.b.bdL.Add(EncryptDecrypt(blockObjects[i].blockID.ToString()));
13.  
14. //Then do the same for the X and Y positions            
15.  
16. fileData.b.bdX.Add(EncryptDecrypt(blockObjects[i].transform.position.x.ToString()));
17.  
18.             fileData.b.bdY.Add(EncryptDecrypt(blockObjects[i].transform.position.y.ToString()));
19.  
20.         }
21.  
22.         // Time to create our XML!
23.         data = SerializeObject(fileData);
24.  
25.         // This is the final resulting XML from the serialization process
26.         CreateXML();
27.        
28.     }
29.  
30. #endregion//Save File

Now to quickly show the "DemoData" class which has been refactored to use Generic Lists

Code (CSharp):

1. [XmlRoot("bData")]
2. public class bData
3. {
4.     // We have to define a default instance of the structure
5.     public LData ld;
6.     // Default constructor doesn't really do anything at the moment
7.     public bData() { }
8.  
9.     // Anything we want to store in the XML file, we define it here
10.     public struct LData
11.     {
12.  
13.         public LData(List<string> id, List<string> x, List<string> y)
14.         {
15.             bdL = id;
16.             bdX = x;
17.             bdY = y;
18.         }
19.  
20.         [XmlAttribute]
21.         public List<string> bdL;
22.  
23.         [XmlAttribute]
24.         public List<string> bdX;
25.  
26.         [XmlAttribute]
27.         public List<string> bdY;
28.  
29.     }
30.  
31.     public LData b = new LData(new List<string>(), new List<string>(), new List<string>());
32.  
33. }

And finally, the Load() Function as well as my deserialize method. This is where the problem crops up

Code (CSharp):

1. LoadXML();
2.  
3.         Debug.LogError("Load(): XML Loaded");
4.  
5.         if(data.ToString() != "") {
6.  
7.             Debug.LogError("Load(): Found XML non-null string");
8.  
9.             // notice how I use a reference to type (SData) here, you need this
10.             // so that the returned object is converted into the correct type
11.             fileData = (bData)DeserializeObject(data);
12.  
13.             Debug.LogError("Load(): Deserialized Data");
14.  
15.             //strings[0]=EncryptDecrypt(playerData.i.gamePlayTime);
16.             //strings[1]=EncryptDecrypt(playerData.i.currentChapter);
17.  
18.             for (int i = 0; i < fileData.b.bdL.Count; i++) {
19.  
20.                 Debug.LogError("Load(): Loading Saved Blocks");
21.  
22.                 Debug.LogError("[SYSTEMBUILDMANAGER.BLOCKLOG]: Block List Line: " + i + ". Contains Block ID: " + fileData.b.bdL[i] + ". Saved at Position: " + fileData.b.bdX[i] + " X, " + fileData.b.bdY[i] + " Y.");
23.  
24.                 GameObject g = SystemPlaceableObjects.PlaceableObjects.PlaceableObjectPrefabs[int.Parse(fileData.b.bdL[i])];
25.  
26.                 float x = float.Parse(fileData.b.bdX[i]);
27.  
28.                 float y = float.Parse(fileData.b.bdY[i]);
29.  
30.                 Vector3 pos = new Vector3(x, y, 0.0F);
31.  
32.                 GameObject block = (GameObject)Instantiate(g, pos, Quaternion.identity);
33.  
34.             }
35.  
36. object DeserializeObject(string pXmlizedString) {
37.         XmlSerializer xs = new XmlSerializer(typeof(bData));
38.         MemoryStream memoryStream = new MemoryStream(StringToUTF8ByteArray(pXmlizedString));
39.         //XmlTextWriter xmlTextWriter = new XmlTextWriter(memoryStream, Encoding.UTF8);
40.         return xs.Deserialize(memoryStream);
41.     }

The idea is the load function runs X times for each List entry, spawning a block with ID equal to the saved ID, at the X and Y positions

 

Why in the world?

Just use the Surrogate for Vector3 serialization, and leave the hard work to the serializer.
You could just define the container, and store the following then:

Code (CSharp):

1.  
2. [System.Serializable]
3. public class Container {
4.     public List<Data> Data = new List<Data>();
5.  
6.    // Fill it
7.    // Container container = new Container();
8.    // container.Data.Add(new Data{ Id = ......
9. }
10.  
11. [System.Serializable]
12. public struct Data {
13.     public string Id;
14.     public Vector3 Pos;
15. }
16.  

Here's an example on how to define Vector3 / Quaternion surrogate.
https://answers.unity.com/questions/956047/serialize-quaternion-or-vector3.html

Then just add the surrogate to the XMLSerializer, or use BinaryFormatter instead.

You'll be able to push the whole container with all the data neccessary, plus get a use-ready list on load, instead of making really nasty workarounds.