尝试创建嵌套的 ScriptableObject："AddAssetToSameFile failed because the other asset is not persistent"

Question

目标： 从项目视图创建嵌套的可编写脚本的 object。

预期：当从项目视图创建容器可编写脚本object的实例时， child 脚本化 object 已创建并附加到容器资产。容器还应保留 child.

的引用

实际： 当我尝试将 child 附加到容器资产时，它失败了。我使用 AssetDatabase.AddObjectToAsset 但出现以下错误消息：

UnityException：将资产添加到 object 失败。
AddAssetToSameFile 失败，因为其他资产不持久

观察：容器创建成功。未创建 child 资产。一旦创建资产，检查器就会显示 child 引用，但在输入容器名称时会显示 Type mismatch。

child object 不是持久化的。我不知道 persistent 在这种情况下是什么意思。我想这可能是我不明白这个问题的原因。

以下是我要实现的简化版本的代码。重现了同样的错误。

容器class

[CreateAssetMenu]
public class Container : ScriptableObject
{
    [SerializeField] private Child child;
        
    private void Reset()
    {
        // Create new child
        child = ScriptableObject.CreateInstance<Child>();

        // Attach child to the container
        AssetDatabase.AddObjectToAsset(child, this); // This line throws exception!

        // Save changes
        AssetDatabase.SaveAssets();
    }
}

Child class

public class Child : ScriptableObject
{
    [SerializeField] public string myString;
}

Answer 1

问题是，在您输入名称之前，新创建的 scriptableObject 尚未持久化。如果您点击 Escape 则它永远不会被创建 ;)

您可以做的是延迟子创建，直到实际创建资产。为了检查这一点，您可以使用 AssetDatabase.Contains

注意：我建议不仅要依赖 Reset，还要使用 OnValidate 和 Awake，以便在有人通过检查员。在那种情况下，我会简单地检查此资产中是否已存在子项，以免重新创建它。

另请注意：UnityEditor 在构建中被完全删除！

=> 如果这意味着用于 Unity 编辑器本身之外的运行时应用程序，请确保将与 UnityEditor 相关的所有内容包装在 pre-processor 标签中

#if UNITY_EDITOR
any code related to UnityEditor namespace
#endif

所以我会做一些事情，例如

using System;
using System.Linq;
using UnityEngine;

#if UNITY_EDITOR
using UnityEditor;
#endif

[CreateAssetMenu]
public class Container : ScriptableObject
{
    [SerializeField]
    private Child child;

    #if UNITY_EDITOR
    private void Awake()
    {
        Init();
    }

    private void OnValidate()
    {
        Init();
    }

    private void Reset()
    {
        Init();
    }

    private void OnDestroy()
    {
        EditorApplication.update -= DelayedInit;
    }

    private void Init()
    {
        // If child is already set -> nothing to do
        if (child)
        {
            return;
        }

        // If this asset already exists initialize immediately
        if (AssetDatabase.Contains(this))
        {
            DelayedInit();
        }
        // otherwise attach a callback to the editor update to re-check repeatedly until it exists
        // this means it is currently being created an the name has not been confirmed yet
        else
        {
            EditorApplication.update -= DelayedInit;
            EditorApplication.update += DelayedInit;
        }
    }

    private void DelayedInit()
    {
        // if this asset dos still not exist do nothing
        // this means it is currently being created and the name not confirmed yet
        if (!AssetDatabase.Contains(this))
        {
            return;
        }

        // as soon as the asset exists remove the callback as we don't need it anymore
        EditorApplication.update -= DelayedInit;

        // first try to find existing child within all assets contained in this asset
        var assets = AssetDatabase.LoadAllAssetsAtPath(AssetDatabase.GetAssetPath(this));
        // you could as well use a loop but this Linq query is a shortcut for finding the first sub asset
        // of type "Child" or "null" if there was none
        child = assets.FirstOrDefault(a => a.GetType() == typeof(Child)) as Child;

        // did we find a child ?
        if (!child)
        {
            // If not create a new child
            child = CreateInstance<Child>();
            // just for convenience I'd always give assets a meaningful name
            child.name = name + "_Child";
            
            // Attach child to the container
            AssetDatabase.AddObjectToAsset(child, this);
        }
        
        // Mark this asset as dirty so it is correctly saved in case we just changed the "child" field
        // without using the "AddObjectToAsset" (which afaik does this automatically)
        EditorUtility.SetDirty(this);

        // Save all changes
        AssetDatabase.SaveAssets();
    }
    #endif
}

尝试创建嵌套的 ScriptableObject："AddAssetToSameFile failed because the other asset is not persistent"

Trying to create nested ScriptableObject: "AddAssetToSameFile failed because the other asset is not persistent"

c#

unity3d

unity3d-editor

unity-editor