internal class EmailMessage

{

    public string From { get; set; }

    public string FromEmail { get; set; }

    public string To { get; set; }

    public string ToEmail { get; set; }

    public string Subject { get; set; }

    public string Body { get; set; }

    public IReadOnlyList<StorageFile> Attachments { get; set; }

}

interface IEmailService

{

    string ApiUser { get; }

    string ApiKey { get; }

    Task<String> SendEmail(EmailMessage message);

}

public async Task<string> SendEmail(EmailMessage message)

{

   HttpClient httpClient = null;

   string responseData = string.Empty;

   try

   {

       using (var postData = new MultipartFormDataContent())

       {

           var subjectContent = new StringContent(message.Subject);

           subjectContent.Headers.ContentDisposition = new ContentDispositionHeaderValue("form-data")

           {

               Name = SubjectParam

           };

           postData.Add(subjectContent);

           var bodyContent = new StringContent(message.Body);

           bodyContent.Headers.ContentDisposition = new ContentDispositionHeaderValue("form-data")

           {

               Name = HtmlParam

           };

           postData.Add(bodyContent);

           //setup api key and api user param

           var apiUserContent = new StringContent(ApiUser);

           apiUserContent.Headers.ContentDisposition = new ContentDispositionHeaderValue("form-data")

           {

               Name = ApiUserParam

           };

           postData.Add(apiUserContent);

           var apiKeyContent = new StringContent(ApiKey);

           apiKeyContent.Headers.ContentDisposition = new ContentDispositionHeaderValue("form-data")

           {

               Name = ApiKeyParam

           };

           postData.Add(apiKeyContent);

           var fromNameContent = new StringContent(message.From);

           fromNameContent.Headers.ContentDisposition = new ContentDispositionHeaderValue("form-data")

           {

               Name = FromNameParam

           };

           postData.Add(fromNameContent);

           var fromContent = new StringContent(message.FromEmail);

           fromContent.Headers.ContentDisposition = new ContentDispositionHeaderValue("form-data")

           {

               Name = From

           };

           postData.Add(fromContent);

           StringContent toContent = new StringContent(message.ToEmail);

           toContent.Headers.ContentDisposition = new ContentDispositionHeaderValue("form-data")

           {

               Name = ToParam

           };

           postData.Add(toContent);

           var toNameContent = new StringContent(message.To);

           toNameContent.Headers.ContentDisposition = new ContentDispositionHeaderValue("form-data")

           {

               Name = ToNameParam

           };

           postData.Add(toNameContent);

           if (message.Attachments.Count() > 0)

           {

               foreach (var attachment in message.Attachments)

               {

                   Stream fs = await attachment.OpenStreamForReadAsync();

                   postData.Add(AddFile(fs, FilesParam, attachment.Name));

               }

           }

           string fullUrl = string.Format("https://{0}{1}", SendGridHost, Uri);

           httpClient = new HttpClient();

           HttpResponseMessage response = await httpClient.PostAsync(new Uri(fullUrl), postData);

           using (HttpContent content = response.Content)

           {

               responseData = await content.ReadAsStringAsync();

           }

           if (response.StatusCode != System.Net.HttpStatusCode.OK)

               throw new Exception(responseData);

       }

       return responseData;

   }

   finally

   {

       if (httpClient != null)

           ((IDisposable)httpClient).Dispose();

   }

}

private StreamContent AddFile(Stream stream, string name, string fileName)

{

    var fileContent = new StreamContent(stream);

    fileContent.Headers.ContentDisposition = new ContentDispositionHeaderValue("form-data")

    {

        Name = string.Format("{0}[{1}]", name, fileName),

        FileName = fileName

    };

    fileContent.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");

    return fileContent;

}

IEmailService emailService = ServiceLocator.Current.GetInstance<IEmailService>();

await emailService.SendEmail(new EmailMessage()

{

    To = "Someone",

    ToEmail = "someone@somecompany.com",

    From = "",

    FromEmail = "",

    Body = "Sending Email from Windows Store apps",

    Subject = "Sending Email from Windows Store apps",

    Attachments = new ReadOnlyCollection<StorageFile>(attachments)

});

HashAlgorithmProvider provider = HashAlgorithmProvider.OpenAlgorithm(HashAlgorithmNames.Sha1);

//hash it

IBuffer hash = provider.HashData(buffer);

CryptographicBuffer.EncodeToBase64String(hash);

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using Windows.Security.Cryptography;

using Windows.Security.Cryptography.Core;

using Windows.Storage.Streams;

    

    internal static class Helper

    {

        public static string ComputeHash(string text)

        {

            string base64Encoded = string.Empty;

            IBuffer buffer = CryptographicBuffer.ConvertStringToBinary(text, BinaryStringEncoding.Utf8);

            HashAlgorithmProvider provider = HashAlgorithmProvider.OpenAlgorithm(HashAlgorithmNames.Sha1);

            //hash it

            IBuffer hash = provider.HashData(buffer);

            base64Encoded = CryptographicBuffer.EncodeToBase64String(hash);

            return base64Encoded;

        }

    }