Throw and Catch an IO exception because the file zxcvb.data doesn't exist
using System.IO;
public class IoError { public static void Main() {
StreamReader f; try{
f = new StreamReader("DoesNotExist.data");
}catch(IOException e) {
System.Console.WriteLine(e);
}
f = new StreamReader("DoesNotExist.data");
}
}