akira32 編程之家 pixnet

Async mechanism uses firebase in Unity. Dropdown control will appear an error when I add an option and call dropDownListCreatedStore.RefreshShownValue(); as below:

And then I modify the positions of await and async. The problem is solved. The Code as below:

public class SellerSetting : MonoBehaviour
{
	public Dropdown dropDownListCreatedStore;
	public InputField InputFieldStoreName;
	public Dropdown dropDownStoreType;

	private string storeName;

	static DatabaseReference reference2;

	private async Task Start()
	{
		reference2 = FirebaseDatabase.GetInstance(Constant.FirebaseDatabaseURL).RootReference.Child("users").Child("stores");

		reference2.ChildAdded += HandleChildAdded;
		reference2.ChildChanged += HandleChildChanged;
		reference2.ChildRemoved += HandleChildRemoved;
		reference2.ChildMoved += HandleChildMoved;

		storeName = "A Store";

		var task  = await Getdata();

		DataSnapshot snapshot = task;

		Debug.Log($"count = {snapshot.ChildrenCount}");

		foreach (DataSnapshot child in snapshot.Children)
		{
			Debug.Log("Received value for leader: " + child.Key);
			await GetType(child);
		}

		dropDownListCreatedStore.RefreshShownValue();
	}

	static async Task Getdata()
	{
		DataSnapshot Task1 = null;

		await reference2.GetValueAsync().ContinueWith(task => {
			if (task.IsFaulted)
			{
				Debug.Log(task.Exception);
			}
			else if (task.IsCompleted)
			{
				
				
			}
			Task1 = task.Result;
		});

		return Task1;
	}

	private async Task GetType(DataSnapshot child)
	{
		DataSnapshot Task1 = null;

		await child.Reference.GetValueAsync().ContinueWith(task =>
		{
			if (task.IsFaulted)
			{
				Debug.Log(task.Exception);
			}
			else if (task.IsCompleted)
			{
				DataSnapshot snapshot = task.Result;

				Debug.Log($"count2 = {snapshot.ChildrenCount}");

				foreach (DataSnapshot child in snapshot.Children)
				{
					//Debug.Log("Received value for store type: " + child.Key);
					//Debug.Log("Received value for store type: " + child.GetRawJsonValue());
					StoreItem item = JsonUtility.FromJson(child.GetRawJsonValue());

					//Debug.Log($" F Store Name = {item.StoreName}");
					//Debug.Log($" F Store Type = {item.StoreType}");
					//Debug.Log($" F Store UserId = {item.UserId}");

					if (child.Key == storeName)
					{
						if (dropDownListCreatedStore.options.Count == 0)
						{
							dropDownListCreatedStore.options.Add(new Dropdown.OptionData(item.StoreType));
							//dropDownListCreatedStore.RefreshShownValue();
						}
						else
						{
							int diffCount = 0;

							for (int index = 0; index < dropDownListCreatedStore.options.Count; index++)
							{
								if (dropDownListCreatedStore.options[index].text != item.StoreType)
								{
									diffCount++;
								}
							}

							if (diffCount == dropDownListCreatedStore.options.Count)
							{
								dropDownListCreatedStore.options.Add(new Dropdown.OptionData(item.StoreType));
								//dropDownListCreatedStore.RefreshShownValue();
							}
						}
					}
				}
			}

			Task1 = task.Result;
		});

		return Task1;
	}