AssetDatabase.Refresh

Description

Import any changed assets.

This will import any assets that have changed their content modification data or have been added-removed to the project folder.

This method implicitly triggers an asset garbage collection (see Resources.UnloadUnusedAssets).

Additional resources: ImportAssetOptions.

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

public class AssetDatabaseExamples : MonoBehaviour
{
    [MenuItem("AssetDatabase/Refresh Example")]
    public static void RefreshExample()
    {
        var folderList = new List<string>{"Textures", "Models", "Sounds"};
        foreach (var folder in folderList)
        {
            Directory.CreateDirectory($"Assets/{folder}");
        }

        foreach (var folder in folderList)
        {
            //Output will be false
            Debug.Log(AssetDatabase.IsValidFolder($"Assets/{folder}"));
        }

        AssetDatabase.Refresh();
        foreach (var folder in folderList)
        {
            //Output will be true
            Debug.Log(AssetDatabase.IsValidFolder($"Assets/{folder}"));
        }
    }
}