System.Windows.Forms.FileDialog.FileRender.SetDirectory C# (CSharp) Method

            public void SetDirectory(string path)
            {
#if UNITY_STANDALONE
                if (path.Length <= 2) return;
                if (System.IO.Directory.Exists(path) == false) return;

                currentPath = path.Replace("\\", "/");

                var files = System.IO.Directory.GetFiles(currentPath, _owner.currentFilter).Select(f => f.Substring(currentPath.Length)).ToArray();
                var dirs = System.IO.Directory.GetDirectories(currentPath).Select(f => f.Substring(currentPath.Length)).ToArray();

                currentFiles = new FileInfo[dirs.Length + files.Length];
                for (int i = 0; i < dirs.Length; i++)
                {
                    currentFiles[i] = new FileInfo();
                    currentFiles[i].IsDirectory = true;
                    currentFiles[i].Name = dirs[i];
                }
                for (int i = dirs.Length; i < dirs.Length + files.Length; i++)
                {
                    currentFiles[i] = new FileInfo();
                    currentFiles[i].Name = files[i - dirs.Length];
                }

                filesTree.Nodes.Clear();
                for (int i = 0; i < currentFiles.Length; i++)
                {
                    TreeNode fileNode = new TreeNode(currentFiles[i].ToString());
                    fileNode.Tag = currentFiles[i];
                    if (currentFiles[i].IsDirectory)
                        fileNode.ImageIndex = 0;
                    else
                        fileNode.ImageIndex = 1;

                    filesTree.Nodes.Add(fileNode);
                }
                filesTree.ExpandAll();

                OnDirectoryChanged();
#endif
            }
            public void Up()