public class FileInOut : MonoBehaviour {

string plainText = "";
TextMesh textmesh;

// Use this for initialization
void Start () {

    textmesh = GameObject.Find ("Text").GetComponent<TextMesh> ();
            //test if Text changes normally
    textmesh.text = "Hallo";

            //create the text file and put text into it
    #if WINDOWS_UWP

    Task task = new Task(

    async () =>
    {
    StorageFolder storageFolder = ApplicationData.Current.LocalFolder;
    StorageFile textFileForWrite = await storageFolder.CreateFileAsync("LocalText.txt");
    await FileIO.WriteTextAsync(textFileForWrite, "Test Start");
    });
    task.Start();
    task.Wait();

    #endif
}

// Update is called once per frame
void Update () {
            //Read the text file and change the text of 3D text to it (not working)
    #if WINDOWS_UWP

    Task task = new Task(

    async () =>
    {
    StorageFolder storageFolder = ApplicationData.Current.LocalFolder;
    StorageFile textFileforRead = await storageFolder.GetFileAsync("LocalText.txt");
    plainText = await FileIO.ReadTextAsync(textFileforRead);
    textmesh.text = plainText;


    });
    task.Start();
    task.Wait();

    #endif
}
}