不允许从 Monobehaviour 调用 persistentDatapath

Question

I also try putting it on start and awake like what the error said but all i got is more error instead.

public class SaveManager : MonoBehaviour
{
      private string SavePath = $"{Application.persistentDataPath}/save.text";

    public void Save()
    {
        var state = LoadFile();
        CaptureState(state);
        SaveFile(state);
    }

    public void Load()
    {
        var state = LoadFile();
        RestoreState(state);
    }

    private Dictionary<string, object> LoadFile()
    {
        if(!File.Exists(SavePath))
        {
            return new Dictionary<string, object>();
        }
        using(FileStream stream = File.Open(SavePath, FileMode.Open))
        {
            var formatter = new BinaryFormatter();
            return(Dictionary<string, object>)formatter.Deserialize(stream);
        }
    }


    private void SaveFile(object state)
    {
        using(var stream = File.Open(SavePath, FileMode.Create))
        {
            var formatter = new BinaryFormatter();
            formatter.Serialize(stream, state);
        }
    }

    private void CaptureState(Dictionary<string, object> state)
    {
        foreach(var saveable in FindObjectsOfType<Entity>())
        {
            state[saveable.Id] = saveable.CaptureState();
        }
    }

    private void RestoreState(Dictionary<string, object> state)
    {
        foreach(var saveable in FindObjectsOfType<Entity>())
        {
            if(state.TryGetValue(saveable.Id, out object value))
            {
                saveable.RestoreState(value);
            }
        }
    }

   
}

Answer 1

Well exactly as the error suggests rather do

private string SavePath;

private void Awake ()
{
    SavePath = $"{Application.persistentDataPath}/save.text";
}

In general rather use Path.Combine which uses the correct path separator depending on the platform

SavePath = Path.Combine(Application.persistentDataPath, "save.text");

Or you could also make it a property but this returns a new string everytime

private string SavePath => Path.Combine(Application.persistentDataPath, "save.text");