如何将文件中的字符串转换为类的实例？

Question

我有一个包含一些变量的类：

public class Species
{
    public string speciesName;
    public string speciesEng;

    public int modHappiness;
    public int modSatiety;
    public int modHydration;
    public int modCommunication;
    public int modVigor;
    public int modCleanliness;

    public Species(string speciesName, string speciesEng, int modHappiness, int modSatiety, int modHydration, int modCommunication, int modVigor, int modCleanliness)
    {
        this.speciesName = speciesName;
        this.speciesEng = speciesEng;
        this.modHappiness = modHappiness;
        this.modSatiety = modSatiety;
        this.modHydration = modHydration;
        this.modCommunication = modCommunication;
        this.modVigor = modVigor;
        this.modCleanliness = modCleanliness;
    }
}

我还有这个类的一些实例：

Species germanShepherd = new Species("Немецкая овчарка", "germanShepherd", 0, 0, 0, 0, 0, 0);

关闭程序后，有关宠物的数据保存到文本文件中：

public bool WriteToFile()
{
    try
    {
        StreamWriter sw = new StreamWriter(name + ".data", false);
        sw.WriteLine(name);
        sw.WriteLine(species.speciesEng);
        sw.WriteLine(gender);

        sw.WriteLine(happiness);
        sw.WriteLine(satiety);
        sw.WriteLine(hydration);
        sw.WriteLine(communication);
        sw.WriteLine(vigor);
        sw.WriteLine(cleanliness);

        sw.WriteLine(trait.traitEng);
        sw.WriteLine(ageMinutes);
        for (int i = 0; i < inventory.Count; i++)
        {
            sw.WriteLine(inventory[i].itemEng);
            sw.WriteLine(inventory[i].count);
        }
        for (int i = 0; i < effects.Count; i++)
        {
            sw.WriteLine(effects[i].effectEng);
        }

        sw.Close();
        MessageBox.Show("Запись выполнена!", "Успех", MessageBoxButtons.OK, MessageBoxIcon.Information);
        return true;
    }
    catch
    {
        MessageBox.Show("Ошибка при записи!", "Ошибка", MessageBoxButtons.OK, MessageBoxIcon.Information);
        return false;
    }
}

保存文件的样子：

Пёс
germanShepherd
Мужской
498500
9500
9500
10000
8750
10000
lazy
0
item1
1
item2
2
item3
3
sick
poisoned

问题是当我尝试将其加载到构造函数内的程序中时，我收到错误 CS0029“无法将字符串转换为 [ClassName]” 构造者：

public Pet(string filePath)
{
    try
    {
        StreamReader sr = new StreamReader(filePath);
        name = sr.ReadLine();
        species = sr.ReadLine();
        gender = sr.ReadLine();
        happiness = int.Parse(sr.ReadLine());
        satiety = int.Parse(sr.ReadLine());
        hydration = int.Parse(sr.ReadLine());
        communication = int.Parse(sr.ReadLine());
        vigor = int.Parse(sr.ReadLine());
        cleanliness = int.Parse(sr.ReadLine());
        ageMinutes = int.Parse(sr.ReadLine());
        trait = sr.ReadLine();
    }
    catch
    {
        throw new Exception("Ошибка чтения сохранения");
    }
}

如何将字符串转换为类的现有实例？

我尝试过显式转换，但错误仍然存在：

species = (Species)sr.ReadLine();

UPD：“宠物”课程全貌：

public class Pet
{
    public string name;
    public Species species;
    public string gender;

    public int happiness;
    public int satiety;
    public int hydration;
    public int communication;
    public int vigor;
    public int cleanliness;

    public Traits trait;
    public int ageMinutes;
    public List<Items> inventory;
    public List<Effect> effects;
    
    /// <summary>
    /// Конструктор нового питомца
    /// </summary>
    /// <param name="name">Имя питомца</param>
    /// <param name="species">Вид питомца</param>
    /// <param name="gender">Пол питомца</param>
    /// <param name="trait">Черта питомца</param>
    public Pet(string name, Species species, string gender, Traits trait)
    {
        this.name = name;
        this.species = species;
        this.gender = gender;
        happiness = 500000;
        satiety = 10000;
        hydration = 10000;
        communication = 10000;
        vigor = 10000;
        cleanliness = 10000;
        ageMinutes = 0;
        this.trait = trait;
        inventory = new List<Items>();
        effects = new List<Effect>();
    }

    public Pet(string filePath)
    {
        try
        {
            StreamReader sr = new StreamReader(filePath);
            name = sr.ReadLine();
            species = (Species)Activator.CreateInstance(null, sr.ReadLine());
            gender = sr.ReadLine();
            happiness = int.Parse(sr.ReadLine());
            satiety = int.Parse(sr.ReadLine());
            hydration = int.Parse(sr.ReadLine());
            communication = int.Parse(sr.ReadLine());
            vigor = int.Parse(sr.ReadLine());
            cleanliness = int.Parse(sr.ReadLine());
            ageMinutes = int.Parse(sr.ReadLine());
            trait = sr.ReadLine();
        }
        catch
        {
            throw new Exception("Ошибка чтения сохранения");
        }
    }
    /// <summary>
    /// Метод записи нового \ перезаписи существующего файла сохранения питомца
    /// </summary>
    /// <returns>Удалось ли сохранить данные</returns>
    public bool WriteToFile()
    {
        try
        {
            StreamWriter sw = new StreamWriter(name + ".data", false);
            sw.WriteLine(name);
            sw.WriteLine(species.speciesEng);
            sw.WriteLine(gender);

            sw.WriteLine(happiness);
            sw.WriteLine(satiety);
            sw.WriteLine(hydration);
            sw.WriteLine(communication);
            sw.WriteLine(vigor);
            sw.WriteLine(cleanliness);

            sw.WriteLine(trait.traitEng);
            sw.WriteLine(ageMinutes);
            for (int i = 0; i < inventory.Count; i++)
            {
                sw.WriteLine(inventory[i].itemEng);
                sw.WriteLine(inventory[i].count);
            }
            for (int i = 0; i < effects.Count; i++)
            {
                sw.WriteLine(effects[i].effectEng);
            }

            sw.Close();
            MessageBox.Show("Запись выполнена!", "Успех", MessageBoxButtons.OK, MessageBoxIcon.Information);
            return true;
        }
        catch
        {
            MessageBox.Show("Ошибка при записи!", "Ошибка", MessageBoxButtons.OK, MessageBoxIcon.Information);
            return false;
        }
    }
    public void AssignItem(Items item) => inventory.Add(item);
    public void AssignEffect(Effect effect)
    {
        effects.Add(effect);
        happiness += effect.modHappiness;
        satiety += effect.modSatiety;
        hydration += effect.modHydration;
        communication += effect.modCommunication;
        vigor += effect.modVigor;
        cleanliness += effect.modCleanliness;
    }

    public void RemoveEffect(Effect effect)
    {
        effects.Remove(effect);
        happiness -= effect.modHappiness;
        satiety -= effect.modSatiety;
        hydration -= effect.modHydration;
        communication -= effect.modCommunication;
        vigor -= effect.modVigor;
        cleanliness -= effect.modCleanliness;
    }

    public void StarveTick()
    {

    }
}

Answer 1

您最初的问题是尝试将文件中的字符串直接分配给 Species 类的实例，导致类型不匹配。要从字符串创建 Species 实例，我们需要实现逻辑以根据从文件读取的数据构造 Species 对象。

我觉得你的代码也有几个设计问题，所以我建议你在代码中遵循这些问题。

使用工厂模式从字符串创建 Species 对象。 将物种创建逻辑集中在 SpeciesFactory 类中。

通过允许轻松扩展以添加新物种定义（可能来自 JSON 文件）来提高可维护性。

public class Species
{
    public string speciesName;
    public string speciesEng;
    public int modHappiness;
    public int modSatiety;
    public int modHydration;
    public int modCommunication;
    public int modVigor;
    public int modCleanliness;

    public Species(string speciesName, string speciesEng, int modHappiness, int modSatiety, int modHydration, int modCommunication, int modVigor, int modCleanliness)
    {
        this.speciesName = speciesName;
        this.speciesEng = speciesEng;
        this.modHappiness = modHappiness;
        this.modSatiety = modSatiety;
        this.modHydration = modHydration;
        this.modCommunication = modCommunication;
        this.modVigor = modVigor;
        this.modCleanliness = modCleanliness;
    }
}


using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text.Json;

public static class SpeciesFactory
{
    private static Dictionary<string, Species> speciesDictionary;

    static SpeciesFactory()
    {
        // Initialize the species from JSON or hardcoded values
        LoadSpeciesFromJson("species.json"); // Optional JSON loading
    }

    private static void LoadSpeciesFromJson(string filePath)
    {
        if (File.Exists(filePath))
        {
            var json = File.ReadAllText(filePath);
            var speciesList = JsonSerializer.Deserialize<List<Species>>(json);

            speciesDictionary = speciesList?.ToDictionary(s => s.speciesEng) 
                                ?? new Dictionary<string, Species>();
        }
        else
        {
            // Fallback to hardcoded values if JSON file is missing
            speciesDictionary = new Dictionary<string, Species>
            {
                { "germanShepherd", new Species("Немецкая овчарка", "germanShepherd", 0, 0, 0, 0, 0, 0) },
                { "species2", new Species("Специес 2", "species2", 1, 1, 1, 1, 1, 1) }
                // Add more species here...
            };
        }
    }

    public static Species CreateSpecies(string speciesEng)
    {
        if (speciesDictionary.TryGetValue(speciesEng, out Species species))
        {
            return species;
        }
        else
        {
            throw new ArgumentException($"Unknown species: {speciesEng}");
        }
    }
}

using System;
using System.IO;

public class Pet
{
    private string name;
    private Species species;
    private string gender;
    private int happiness;
    private int satiety;
    private int hydration;
    private int communication;
    private int vigor;
    private int cleanliness;
    private int ageMinutes;
    private string trait;

    public Pet(string filePath)
    {
        try
        {
            using (StreamReader sr = new StreamReader(filePath))
            {
                name = sr.ReadLine();

                // Use SpeciesFactory to create the Species instance
                string speciesEng = sr.ReadLine();
                species = SpeciesFactory.CreateSpecies(speciesEng);

                gender = sr.ReadLine();
                happiness = int.Parse(sr.ReadLine());
                satiety = int.Parse(sr.ReadLine());
                hydration = int.Parse(sr.ReadLine());
                communication = int.Parse(sr.ReadLine());
                vigor = int.Parse(sr.ReadLine());
                cleanliness = int.Parse(sr.ReadLine());
                ageMinutes = int.Parse(sr.ReadLine());
                trait = sr.ReadLine();
            }
        }
        catch (Exception ex)
        {
            throw new Exception("Ошибка чтения сохранения: " + ex.Message);
        }
    }
}

//This optional JSON file (species.json) can be used to define species dynamically:

[
    {
        "speciesName": "Немецкая овчарка",
        "speciesEng": "germanShepherd",
        "modHappiness": 0,
        "modSatiety": 0,
        "modHydration": 0,
        "modCommunication": 0,
        "modVigor": 0,
        "modCleanliness": 0
    },
    {
        "speciesName": "Специес 2",
        "speciesEng": "species2",
        "modHappiness": 1,
        "modSatiety": 1,
        "modHydration": 1,
        "modCommunication": 1,
        "modVigor": 1,
        "modCleanliness": 1
    }
]

工厂模式：集中物种创建并提高可维护性。

错误处理：通过清晰的错误消息改进故障排除。

可扩展性：允许通过在 JSON 文件或硬编码字典中添加新物种来进行未来扩展。