using Windows.Storage; using Windows.Storage.Pickers; async void PickFiles() { var picker = new FileOpenPicker(); picker.FileTypeFilter.Add(".txt"); picker.FileTypeFilter.Add(".doc"); picker.FileTypeFilter.Add(".docx"); var files = await picker.PickMultipleFilesAsync(); if (files != null) { foreach (StorageFile file in files) { // Process file } } }In this example, a file picker is created with its allowed file formats set to .txt, .doc, and .docx. The PickMultipleFilesAsync method is then called and the returned files are iterated over, allowing for individual processing of each file. Package library: Windows.Storage.Pickers.