Question

我目前正在尝试从Firebase数据库中检索数据。当前功能我只能显示数据。但是，在检索数据之后，我无法传递给其他变量或传递给构造函数。

功能

public Ally ReadCard() // 
{
    Ally ally = new Ally();[enter image description here][1]
    FirebaseDatabase.DefaultInstance.GetReference("Cards").GetValueAsync().ContinueWith(task =>
    {
        if (task.IsFaulted)
        {

        }
        else if (task.IsCompleted)
        {

        }

        DataSnapshot dataSnapshot = task.Result;
        var json = dataSnapshot.Child("P001-0000-0001").GetRawJsonValue();
        AllyBean card = JsonUtility.FromJson<AllyBean>(json);

        Debug.Log("Card Description : " + card.CardDescription);
        Debug.Log("Card Name : " + card.CardName);
        Debug.Log("Card Type : " + card.CardType);
        Debug.Log("Card Atk : " + card.AllyBeanProperties.Atk);
        Debug.Log("Card Hp : " + card.AllyBeanProperties.Hp);
        ally = new Ally(card.CardName, card.CardDescription, card.CardType, card.AllyBeanProperties.Atk, card.AllyBeanProperties.Hp); 

    });
    return ally;
}

此功能的目的是允许我检索数据并将其转换为类对象。

主程序

 void Start()
{
    databaseUtils = new DatabaseUtils();
    Debug.Log( "Main value : " + databaseUtils.ReadCard().CardName); //trying to retrieve data from database
}

问题

但是，基于控制台，数据仅显示在Debug.Log（）中。数据似乎没有插入到构造函数中。

    Debug.Log("Card Description : " + card.CardDescription); 
    Debug.Log("Card Name : " + card.CardName);
    Debug.Log("Card Type : " + card.CardType);
    Debug.Log("Card Atk : " + card.AllyBeanProperties.Atk);
    Debug.Log("Card Hp : " + card.AllyBeanProperties.Hp);
    ally = new Ally(card.CardName, card.CardDescription, card.CardType, card.AllyBeanProperties.Atk, card.AllyBeanProperties.Hp);  // new ally object is empty

Debug Result

Firebase Structure

欢迎任何帮助。谢谢

Answer 1

更改

主文件

DatabaseUtils databaseUtils;

async void Start()
{
    databaseUtils = new DatabaseUtils();
    Ally ally = new Ally("card name 12", "card description 12", CardType.Ally, 20, 30);
    databaseUtils.AddCard(ally);
    await databaseUtils.ReadCard();

    Debug.Log(databaseUtils.GetCard().CardName);
}

读取功能

public async Task ReadCard()
{
    await FirebaseDatabase.DefaultInstance.GetReference("Cards").GetValueAsync().ContinueWith(task =>
    {
        if (task.IsFaulted)
        {

        }
        else if (task.IsCompleted)
        {
            DataSnapshot dataSnapshot = task.Result;
            var json = dataSnapshot.Child("P001-0000-0001").GetRawJsonValue();
            Ally card = JsonUtility.FromJson<Ally>(json);

            Debug.Log(card.CardDescription);
            Debug.Log(card.CardName);
            Debug.Log(card.CardType);

            Ally ally = new Ally(card.CardName, card.CardDescription, card.CardType, card.Atk, card.Hp);
            SetCard(ally);
        }

    });
}

public void SetCard(Card card)
{
    this.card = card;
}

public Card GetCard()
{
    return card;
}

注意

我收到的“异步功能”在C＃4'错误代码中不可用。我更新了VS，并改用了donet4

Answer 2

我是该领域的新手，但我希望我的回答对这个问题有所帮助。：-）

以下代码段提供了从Firebase实时数据库下载数据并将其分配给不同变量并在控制台中显示它们的最简单方法。我认为这可能会给您您想要的东西。

注意：-当我们处理API通信类任务时，最好坚持使用异步编程。

考虑一下您的数据是如何在Firebase中形成的。

根据数据库创建模型类。（这可用于上传和下载过程）

internal class StudentDetails
 {
     public string id { get; set; }
     public string Name { get; set; }
     public string Age { get; set; }
     public string Address { get; set; }
 }

创建一个异步方法来下载数据并执行所需的操作。

public class Demo                                                   
 {                                                                   
 IFirebaseClient firebaseclient2;
 int id, age = 0;
 string name, address = "";                                                        

  public async void DownloadStudentDetails()
 {
     FirebaseResponse firebaseResponse = await firebaseclient2.GetTaskAsync("Student");
     StudentDetails student = firebaseResponse.ResultAs<StudentDetails>();
     id = Convert.ToInt32(student.id.Trim());
     name = student.Name.Trim();
     address = student.Address.Trim();
     age = Convert.ToInt32(student.Age.Trim());
     Console.WriteLine(id);
     Console.WriteLine(name);
     Console.WriteLine(age);
     Console.WriteLine(address);
 }

}

在C＃

2 个答案: