How to check a List for values

Question

Hi,

 

I have a List values = new List();

 

values.add("0");This 

values.add("1");

values.add("9)";

 

Only values 0 and 9 are valid so therefore I must check if the list above has values that are different from the values 0 and 9. I need help with that from someone that is experienced in C#.

 

I have tried with this;

 

This if statement will always be true because I only check for 0 and 9.

if (values.ContainshT("0") && values.Contains("9"))

This if statement will also be true because there is an item that is different from 0 and 9.

if (!values.ContainshT("0") && !values.Contains("9"))

 How to check if items exist other than 0 and 9 it is false and if only items 0 and 9 exist then it is true.