Load All Prefabs In Directory

gistfile1.cs

using System.Collections.Generic;
using UnityEngine;
using UnityEditor;
using System.IO;

public static class PrefabLoader
{
    //So, there's no "load all assets in directory" function in unity. 
    //I guess this is to avoid people using Prefabs as "data blobs". 
    //They'd rather you use ScriptableObjects... which is fine in some cases, 
    //but sometimes the thing you're blobbing is just a bunch of child transforms anyway,
    //so it's huge buckets of sweat to reproduce the scene tools unity already has. 
    
    //The "AssetsDatabase.LoadAllAssetsAtPath" refers to /compound/ raw assets,
    //like maya files. But it doesn't care about humble prefabs, 
    //which are more like compounds of assets, rather than raw assets.
    
    //This function collates all the the behaviours you want in the directory you point it at. The path is relative to your Assets.
    //i.e. "Assets/MyDirectory/"
    //It returns the Prefab References, remember! Not instantiated scene objects! 
    //So it's only used for *editor-side* tools. Not run time.
    //Quite useful in conjunction with "PrefabUtility".
    public static List<T> LoadAllPrefabsOfType<T>(string path) where T : MonoBehaviour
    {
        if (path != "")
        {
            if (path.EndsWith("/"))
            {
                path = path.TrimEnd('/');
            }
        }

        DirectoryInfo dirInfo = new DirectoryInfo(path);
        FileInfo[] fileInf = dirInfo.GetFiles("*.prefab");

        //loop through directory loading the game object and checking if it has the component you want
        List<T> prefabComponents = new List<T>();
        foreach (FileInfo fileInfo in fileInf)
        {
            string fullPath = fileInfo.FullName.Replace(@"\","/");
            string assetPath = "Assets" + fullPath.Replace(Application.dataPath, "");
            GameObject prefab = AssetDatabase.LoadAssetAtPath(assetPath, typeof(GameObject)) as GameObject;

            if(prefab!= null)
            {
                T hasT = prefab.GetComponent<T>();
                if (hasT !=null)
                {
                    prefabComponents.Add(hasT);
                }
            }
        }
        return prefabComponents;
    }

}

Personally I think static methods are just evil. I could see maybe see a justification if this were an extension method. Static methods/properties makes completely untestable code. I have all my game objects in a dll with DryIoc, so I can fully mock make game objects before using them in Unity. Makes for much faster development.

So, I re-modified this so you can apply an Func parameter. For instance, I want all prefabs to be loaded and I have a MonoBehavior that specifies it's scene name it can be loaded in.

using this code I can add custom validation code within the method.

` public List LoadPrefabsByScene(string sceneName)
{
return LoadAllPrefabsOfType("Assets/Resources/Prefabs", (x) => x.Scenes.Contains(sceneName))..Select(x => x.gameObject).ToList();
}

public List<T> LoadAllPrefabsOfType<T>(string path, Func<T, bool> evaluate) where T : MonoBehaviour
{
    if (path != "")
    {
        if (path.EndsWith("/"))
        {
            path = path.TrimEnd('/');
        }
    }

    DirectoryInfo dirInfo = new DirectoryInfo(path);
    FileInfo[] fileInf = dirInfo.GetFiles("*.prefab", SearchOption.AllDirectories);

    //loop through directory loading the game object and checking if it has the component you want
    List<T> prefabComponents = new List<T>();
    foreach (FileInfo fileInfo in fileInf)
    {
        string fullPath = fileInfo.FullName.Replace(@"\", "/");
        string assetPath = "Assets" + fullPath.Replace(Application.dataPath, "");
        GameObject prefab = AssetDatabase.LoadAssetAtPath(assetPath, typeof(GameObject)) as GameObject;

        if (prefab != null)
        {
            T hasT = prefab.GetComponent<T>();
            if (hasT != null)
            {
                // validate the expression
                if (evaluate.Invoke(hasT))
                {
                    prefabComponents.Add(hasT);
                }
            }
        }
    }
    return prefabComponents;
}`

Hope this helps someone, Cheers!