title: I couldn't see my extension method
body: <p>I couldn't see this method as extension method in MainWindow.xaml.cs , why</p>
  
  <p>In MainWindow , 
  I added : 
      using WpfApplication1_WPF.Classes;</p>
  
  <p>please, advise me.</p>
  
  <p>This is the code:</p>
  
  <pre><code>using System;
  using System.Collections.Generic;
  using System.Linq;
  using System.Text;
  using System.Security.Cryptography;
  using System.Runtime.CompilerServices;
  using System.Data.Objects;
  
  namespace WpfApplication1_WPF.Classes
  {
  public static class Extensions 
  {
        //1-Convert the user input to hash 
        public static String Hashed(String dataToHash)
        {
           //Convert dataToHash to byte array
           byte[] plainTextBytes = Encoding.Unicode.GetBytes(dataToHash);
  
           //Computer hash of bytes using SHA256 (256 bit hash value)
           //Convert text to hash by using ComputerHash function in SHA256Managed algorithm
           byte[] hash = new SHA256Managed().ComputeHash(plainTextBytes);
  
           //Return hashed bytes as encoded string 
           //[convert hash byte to string to be saved in DB]
           return Convert.ToBase64String(hash);
         }
    }
  }
  </code></pre>