Windows phone 8 - Download html code not wating

I am downloading html code 5 times and I want to wait that phone can download html code and turn into text. Can I do that, that my general function wait for respond and then continue working?

public string izvuci_sliku(string linka)
{
     WebClient webclient = new WebClient();
     link = "";
     webclient.DownloadStringCompleted += webclient_DownloadStringCompleted3;
     webclient.DownloadStringAsync(new Uri(linka));
     //wait upper line and then go one
     return "";
}