Download file with progress bar in Xamarin Forms - asynchronous

Question

I am trying to make a download page in Xamarin Forms (PCL, so WebClient is not usable) with a Download progress bar. I have used the following information from Xamarin, but without success:
http://developer.xamarin.com/recipes/ios/network/web_requests/download_a_file/
http://developer.xamarin.com/recipes/cross-platform/networking/download_progress/
This is my current code (with a working progress bar):
using System;
using System.Collections.Generic;
using Xamarin.Forms;
using System.Net.Http;
using System.IO;
using System.Threading.Tasks;
namespace DownloadExample
{
public partial class DownloadPage : ContentPage
{
public DownloadPage ()
{
InitializeComponent ();
DownloadFile("https://upload.wikimedia.org/wikipedia/commons/3/3d/LARGE_elevation.jpg");
}
private async Task<long> DownloadFile(string url)
{
long receivedBytes = 0;
long totalBytes = 0;
HttpClient client = new HttpClient ();
using (var stream = await client.GetStreamAsync(url)) {
byte[] buffer = new byte[4096];
totalBytes = stream.Length;
for (;;) {
int bytesRead = await stream.ReadAsync (buffer, 0, buffer.Length);
if (bytesRead == 0) {
await Task.Yield ();
break;
}
receivedBytes += bytesRead;
int received = unchecked((int)receivedBytes);
int total = unchecked((int)totalBytes);
double percentage = ((float) received) / total;
progressBar1.Progress = percentage;
}
}
return receivedBytes;
}
}
}
Now, I need to save the file to my local storage. But, in this example, I'm not getting the file content, so I can't write it to my local storage. What do I need to change in the code to make this possible?
FYI: In this example, I'm downloading an image, but it will be a .pdf / .doc / .docx in feature.
Thanks in advance.
BR, FG

Answer 1

Think your article,I also solved download file
WebClient client = new WebClient();
using (var stream = await client.OpenReadTaskAsync(Download point))
{
using (MemoryStream ms = new MemoryStream())
{
var buffer = new byte[BufferSize];
int read = 0;
totalBytes = Int32.Parse(client.ResponseHeaders[HttpResponseHeader.ContentLength]);
while ((read = await stream.ReadAsync(buffer, 0, buffer.Length)) > 0)
{
ms.Write(buffer, 0, read);//important : receive every buffer
receivedBytes += read;
received = unchecked((int)receivedBytes);
total = unchecked((int)totalBytes);
percentage = ((float)received) / total;
progressBar1.Progress = percentage;
labProg.Text = AppResources.MsgDownloadprogress + Math.Truncate(percentage * 100).ToString() + "%";
}//END while
Stream ALLstream = new MemoryStream(ms.ToArray());//important change Stream
App.APK.GenApkFile(ALLstream);//change APK file and save memory of phone
}//END using (MemoryStream
stream.Close();
}//END using (var stream

Answer 2

You actually copy the file content to your buffer inside the for loop. Concat the buffer content each run of that loop into a new byte[] fileContentBuffer and you have access to the contents which you can save in the local storage.