PasswordVault.cs

using System;
using System.Collections.Generic;
using Windows.Security.Credentials;
namespace utilities
{
class PasswordVault_Utility
{
const int ElementNotFound = unchecked((int)0x80070490);
//private resource = "www.example.com";
//private userName = "userName";
//private password = "password";
//private vault = new PasswordVault();

static public void SaveCredential(string resource, 
                                  string userName, 
                                  string password)
{
    var vault = new PasswordVault();
    var cred = new PasswordCredential(resource, userName, password);
    //Add credential or Replaces any existing credential with the same 
    //resource and user name.
    vault.Add(cred);
}

static public IReadOnlyList<PasswordCredential> 
                RetrieveCredentials(string resource, 
                                    string userName)
{
    var vault = new PasswordVault();
    IReadOnlyList<PasswordCredential> creds = null;
    try
    {
        if (resource == "" && userName == "")
        {
            // Both resource and user name are empty: 
            //Use retrieveAll().
            creds = vault.RetrieveAll();
        }
        else if (userName == "")
        {
            // Resource is provided but no user name: 
            //Use findAllByResource().
            creds = vault.FindAllByResource(resource);
        }
        else if (resource == "")
        {
            // User name is provided but no resource: 
            //Use findByUserName().
            creds = vault.FindAllByUserName(userName);
        }
        else
        {
            // Both resource and user name are provided: 
            // Use retrieve().
            PasswordCredential cred = vault.Retrieve(resource, userName);
            // Add it to our results if the retrieval was successful.
            if (cred != null)
            {
                creds = new List<PasswordCredential>() { cred };
            }
        }
    }
    catch (Exception e)
    {
        // The credential retrieval functions raise an 
        //"Element not found" exception if there were no matches.
        if (e.HResult != ElementNotFound) throw; else creds = 
                                    new List<PasswordCredential>();
    }
    return creds;
}

static public bool RemoveCredentials(PasswordCredential cred)
{
    var vault = new PasswordVault();
    bool doen = false;
    try
    {
        vault.Remove(cred);
        doen = true;
    }
    catch (Exception e)
    {
        // Ignore exception if the credential was already removed.
        if (e.HResult != ElementNotFound)
        {
            throw;
        }
    }
    return doen;
}
}
}