如何防止出现 CS0161 错误？ - 团结

Question

i am using unity 2018. I want to save my data in my game but i keep getting the error: "Assets/Assets/Scripts/SaveSystem.cs(15,30): error CS0161: `SaveSystem.LoadPlayer()': not all code paths return a value"

This is the current code im using:

using UnityEngine;
using System.IO;
using System.Runtime.Serialization.Formatters.Binary;

public static class SaveSystem {
    public static void SavePlayer(GlobalCookies player)
    {
        BinaryFormatter formatter = new BinaryFormatter();
        string path = Application.persistentDataPath + "playerdata.bcdata";
        FileStream stream = new FileStream(path, FileMode.Create);
        PlayerData data = new PlayerData(player);
        formatter.Serialize(stream, data);
        stream.Close();
    }
    public static PlayerData LoadPlayer()
    {
        string path = Application.persistentDataPath + "playerdata.bcdata";
        if (File.Exists(path))
        {
            BinaryFormatter formatter = new BinaryFormatter();
            FileStream stream = new FileStream(path, FileMode.Open);
            PlayerData data = formatter.Deserialize(stream) as PlayerData;
            stream.Close();
            return data;
        }
        else
        {
            Debug.LogError("Save file 'playerdata.bcdata' was not found, please reinstall the missing file (error in: " + path + ")");
        }

    }

}

Answer 1

Under your Debug.LogError call, add throw new InvalidOperationException();

Like so:

public static PlayerData LoadPlayer()
    {
        string path = Application.persistentDataPath + "playerdata.bcdata";
        if (File.Exists(path))
        {
            BinaryFormatter formatter = new BinaryFormatter();
            FileStream stream = new FileStream(path, FileMode.Open);
            PlayerData data = formatter.Deserialize(stream) as PlayerData;
            stream.Close();
            return data;
        }
        else
        {
            String message = "Save file 'playerdata.bcdata' was not found, please reinstall the missing file (error in: " + path + ")";
            Debug.LogError( message  );
            throw new InvalidOperationException( message );
        }

    }

Answer 2

public static PlayerData LoadPlayer()
{
    string path = Application.persistentDataPath + "playerdata.bcdata";
    if (File.Exists(path))
    {
        BinaryFormatter formatter = new BinaryFormatter();
        FileStream stream = new FileStream(path, FileMode.Open);
        PlayerData data = formatter.Deserialize(stream) as PlayerData;
        stream.Close();
        return data;
    }
    else
    {
        Debug.LogError("Save file 'playerdata.bcdata' was not found, please reinstall the missing file (error in: " + path + ")");
        return null;
    }

}

Not all paths returns a value error happens because your function expects a return value. You are returning data on "if" part but not on "else" part of function.

It's like it's asking you "Okay I am returning data to you if I found it but what if I couldn't find it?".