Unity C# InvalidCastException: Cannot cast from source type to destination type

Question

I'm currently encountering an error in a large scale project.

Code below:

public void SaveFileExists(){

    Debug.Log ("SaveFileExists was called.");

    //GameObject.Find ("_Scripts").GetComponent<SaveGame> ().Load ();
    UserData userdata = null;

    //Creating a new BinaryFormatter
    BinaryFormatter bf = new BinaryFormatter ();

    //Making a file which now contains the Un-Serialized File
    FileStream file = File.Open (Application.persistentDataPath + ("/UserData." + accountLoginAttempt), FileMode.Open);

    //Assigning the values of the saved file to the new file
    //UserData newData = (UserData)bf.Deserialize (file);

    userdata = bf.Deserialize(file) as UserData;

    //Assigning the values from the save file to the variables in this script.
    accountLoginAttempt = userdata.username;
    accountLevel = userdata.userlevel;

    //Assinging the values from this script to the _PlayerManager script. (This is where the UI gets it's info).
    GameObject.Find ("_AccountInfoSaveHolder").GetComponent<HoldInfo> ().UserInfo = accountLoginAttempt;
    GameObject.Find ("_AccountInfoSaveHolder").GetComponent<HoldInfo> ().UserLevel = accountLevel;

    errortext.text = "Login Successful.";
    Canvas.ForceUpdateCanvases ();
}

The serialised field is also below:

[System.Serializable]
class UserData{
public string username;
public int userlevel;
}

I am trying to load a savefile which is stored in the Application.persistentDataPath. Assigning the UserData.username and UserData.userlevel to variables in my script.

The error I am receiving is:

InvalidCastException: Cannot cast from source type to destination type.

Further Details:

LoginScript.SaveFileExists () (at Assets/Scripts/AccountSystem/LoginScript.cs:126) LoginScript.OnLoginClick () (at Assets/Scripts/AccountSystem/LoginScript.cs:104) UnityEngine.Events.InvokableCall.Invoke (System.Object[] args) (at /Users/builduser/buildslave/unity/build/Runtime/Export/UnityEvent.cs:153) UnityEngine.Events.InvokableCallList.Invoke (System.Object[] parameters) (at /Users/builduser/buildslave/unity/build/Runtime/Export/UnityEvent.cs:634) UnityEngine.Events.UnityEventBase.Invoke (System.Object[] parameters) (at /Users/builduser/buildslave/unity/build/Runtime/Export/UnityEvent.cs:769) UnityEngine.Events.UnityEvent.Invoke () (at /Users/builduser/buildslave/unity/build/Runtime/Export/UnityEvent_0.cs:53) UnityEngine.UI.Button.Press () (at /Users/builduser/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/UI/Core/Button.cs:35) UnityEngine.UI.Button.OnPointerClick (UnityEngine.EventSystems.PointerEventData eventData) (at /Users/builduser/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/UI/Core/Button.cs:44) UnityEngine.EventSystems.ExecuteEvents.Execute (IPointerClickHandler handler, UnityEngine.EventSystems.BaseEventData eventData) (at /Users/builduser/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/EventSystem/ExecuteEvents.cs:52) UnityEngine.EventSystems.ExecuteEvents.Execute[IPointerClickHandler] (UnityEngine.GameObject target, UnityEngine.EventSystems.BaseEventData eventData, UnityEngine.EventSystems.EventFunction`1 functor) (at /Users/builduser/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/EventSystem/ExecuteEvents.cs:269) UnityEngine.EventSystems.EventSystem:Update()

EDIT:

SaveGame.cs:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System.Runtime.Serialization.Formatters.Binary; 
using System.IO;
using UnityEngine.SceneManagement;

public class SaveGame : MonoBehaviour {

//Saved Variables
[Header("Saved Variables")]
public string savedname;
public string attemptedlogin;
public int savedlevel;

//Loaded Variables
[Header("Loaded Variables")]
public string loadedname;
public int loadedlevel;


public void Awake(){

    if (SceneManager.GetActiveScene ().name == "GameScene") {
        Load ();
    }
}

public void Save(){

    savedname = GameObject.Find ("_Scripts").GetComponent<PlayerManager> ().PlayerName;
    savedlevel = GameObject.Find ("_Scripts").GetComponent<PlayerManager> ().UserLevel;

    BinaryFormatter bf = new BinaryFormatter();

    FileStream file = File.Open(Application.persistentDataPath + ("/UserData." + savedname), FileMode.Create);

    UserData newData = new UserData();

    newData.username = savedname;
    newData.userlevel = savedlevel;

    bf.Serialize(file, newData);
    file.Close();
}
}

I also removed all System.Serializable class's throughout my scripts and made a script called UserDataSerialize.cs which contains:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

[System.Serializable]
class UserData{
    public string username;
    public int userlevel;
}

Now the error I get is:

TypeLoadException: Could not load type 'SaveGame+UserData'.
System.Reflection.Assembly.GetType (System.String name, Boolean throwOnError, Boolean ignoreCase) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/Assembly.cs:398)
System.Reflection.Assembly.GetType (System.String name, Boolean throwOnError) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/Assembly.cs:381)
System.Runtime.Serialization.Formatters.Binary.ObjectReader.GetDeserializationType (Int64 assemblyId, System.String className) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Runtime.Serialization.Formatters.Binary/ObjectReader.cs:833)
System.Runtime.Serialization.Formatters.Binary.ObjectReader.ReadTypeMetadata (System.IO.BinaryReader reader, Boolean isRuntimeObject, Boolean hasTypeInfo) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Runtime.Serialization.Formatters.Binary/ObjectReader.cs:637)
System.Runtime.Serialization.Formatters.Binary.ObjectReader.ReadObjectInstance (System.IO.BinaryReader reader, Boolean isRuntimeObject, Boolean hasTypeInfo, System.Int64& objectId, System.Object& value, System.Runtime.Serialization.SerializationInfo& info) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Runtime.Serialization.Formatters.Binary/ObjectReader.cs:269)
System.Runtime.Serialization.Formatters.Binary.ObjectReader.ReadObject (BinaryElement element, System.IO.BinaryReader reader, System.Int64& objectId, System.Object& value, System.Runtime.Serialization.SerializationInfo& info) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Runtime.Serialization.Formatters.Binary/ObjectReader.cs:195)
System.Runtime.Serialization.Formatters.Binary.ObjectReader.ReadObject (BinaryElement element, System.IO.BinaryReader reader, System.Int64& objectId, System.Object& value, System.Runtime.Serialization.SerializationInfo& info) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Runtime.Serialization.Formatters.Binary/ObjectReader.cs:223)
System.Runtime.Serialization.Formatters.Binary.ObjectReader.ReadNextObject (BinaryElement element, System.IO.BinaryReader reader) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Runtime.Serialization.Formatters.Binary/ObjectReader.cs:130)
System.Runtime.Serialization.Formatters.Binary.ObjectReader.ReadObjectGraph (BinaryElement elem, System.IO.BinaryReader reader, Boolean readHeaders, System.Object& result, System.Runtime.Remoting.Messaging.Header[]& headers) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Runtime.Serialization.Formatters.Binary/ObjectReader.cs:104)
System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.NoCheckDeserialize (System.IO.Stream serializationStream, System.Runtime.Remoting.Messaging.HeaderHandler handler) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Runtime.Serialization.Formatters.Binary/BinaryFormatter.cs:179)
System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize (System.IO.Stream serializationStream) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Runtime.Serialization.Formatters.Binary/BinaryFormatter.cs:136)
LoginScript.SaveFileExists () (at Assets/Scripts/AccountSystem/LoginScript.cs:111)
LoginScript.OnLoginClick () (at Assets/Scripts/AccountSystem/LoginScript.cs:84)
UnityEngine.Events.InvokableCall.Invoke (System.Object[] args) (at /Users/builduser/buildslave/unity/build/Runtime/Export/UnityEvent.cs:153)
UnityEngine.Events.InvokableCallList.Invoke (System.Object[] parameters) (at /Users/builduser/buildslave/unity/build/Runtime/Export/UnityEvent.cs:634)
UnityEngine.Events.UnityEventBase.Invoke (System.Object[] parameters) (at /Users/builduser/buildslave/unity/build/Runtime/Export/UnityEvent.cs:769)
UnityEngine.Events.UnityEvent.Invoke () (at /Users/builduser/buildslave/unity/build/Runtime/Export/UnityEvent_0.cs:53)
UnityEngine.UI.Button.Press () (at /Users/builduser/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/UI/Core/Button.cs:35)
UnityEngine.UI.Button.OnPointerClick (UnityEngine.EventSystems.PointerEventData eventData) (at /Users/builduser/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/UI/Core/Button.cs:44)
UnityEngine.EventSystems.ExecuteEvents.Execute (IPointerClickHandler handler, UnityEngine.EventSystems.BaseEventData eventData) (at /Users/builduser/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/EventSystem/ExecuteEvents.cs:52)
UnityEngine.EventSystems.ExecuteEvents.Execute[IPointerClickHandler] (UnityEngine.GameObject target, UnityEngine.EventSystems.BaseEventData eventData, UnityEngine.EventSystems.EventFunction`1 functor) (at /Users/builduser/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/EventSystem/ExecuteEvents.cs:269)
UnityEngine.EventSystems.EventSystem:Update()

The only explicit cast is the result of BinaryFormatter.Deserialize to type UserData. Are you sure the file is in the format you expect? — Andy Lamb
– Andy Lamb, Commented Jun 20, 2017 at 5:55
@AndyLamb I think so? What exactly do you mean by the format it is expected. The class 'UserData' is a string 'username' followed by an int 'userlevel'. — Valkarth
– Valkarth, Commented Jun 20, 2017 at 6:08
What is your Unity version? Can you also put your save code in your question? — Programmer
– Programmer, Commented Jun 20, 2017 at 6:08
Unity 5.5.1f1 Personal (64bit) on Mac. SaveGame.cs: public void InitializeSave(){ savedname = GameObject.Find ("_Scripts").GetComponent<PlayerManager> ().PlayerName; savedlevel = GameObject.Find ("_Scripts").GetComponent<PlayerManager> ().UserLevel; Save (); } MORE CODE IN NEXT COMMENT — Valkarth
– Valkarth, Commented Jun 20, 2017 at 6:10
Part 2 public void Save(){ BinaryFormatter bf = new BinaryFormatter(); //Creates a new file at the directory of the save path. FileStream file = File.Open(Application.persistentDataPath + ("/UserData." + savedname), FileMode.Create); //Clearing temp files and starting from a new file UserData newData = new UserData(); //Assigning Variables newData.username = savedname; newData.userlevel = savedlevel; //Encodes newData to file. bf.Serialize(file, newData); file.Close(); } — Valkarth
– Valkarth, Commented Jun 20, 2017 at 6:13

Valkarth · Accepted Answer · 2017-06-20 06:55:49Z

1

Solution:

Create another script which only contains:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

[System.Serializable]
class UserData{
    public string username;
    public int userlevel;
}

And delete all other System.Serialize class's of the same name throughout other scripts.

answered Jun 20, 2017 at 6:55

Valkarth

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1 Comment

Programmer Over a year ago

Great. Funny how that works in Unity 5.6 but not in 5.5. I guess Unity has fixed this problem.

Truth · Accepted Answer · 2020-02-05 14:45:31Z

0

Maybe not a problem for everyone, but this helped me: In the course of building my save structure, I first saved one type of object, but then switched to a different one. My game was set to load before there was an opportunity to save, and so I was loading an old class without having saved over it with the new class. I was able to resolve the problem by disabling load, playing the game for a turn, saving, and then turning load on again.

answered Feb 5, 2020 at 14:45

Truth

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