In windows phone 7 I'm doing a simple async lookup to find an image by uri and set the returned binary as the source for an image control.
public object SetImageFromUri(string uri)
{
var wc = new WebClient();
wc.OpenReadCompleted += new OpenReadCompletedEventHandler(wc_OpenReadCompleted);
wc.OpenReadAsync(new Uri(uri), wc);
return null;
}
void wc_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
{
if (e.Error == null && !e.Cancelled)
{
var image = new BitmapImage();
image.SetSource(e.Result);
//e.Result has a property in the memory stream labeled finalUri
//someImageControl.Source = image;
}
}
My question is- how can I pull out the final uri property from the e.Result so I can see what image control it's associated with
Thank you in advance
Instead of passing the WebClient through as the second parameter, pass the Uri (or some other piece of usefule state information)
wc.OpenReadAsync(new Uri(uri), uri);
You can then access this in your callback
var uri = (string)e.UserState;
Due to specific restrictions implemented in the Reflection mechanism, you cannot access internal content from sandboxed code. Ultimately, you would want to use something like this:
FieldInfo f = e.Result.GetType().GetField("_finalUri", BindingFlags.NonPublic | BindingFlags.DeclaredOnly | BindingFlags.Instance);
Uri n = (Uri)f.GetValue(e.Result);
However, this will cause a FieldAccessException. If you are not using a redirect URI, then you can simply reuse the parameter that is initially passed to your method. If not, you need to check HttpWebRequest and follow the idea I outlined a couple of days ago.
You could also just bind directly to the Image, and use the LowProfileImageLoader, to avoid it blocking the UI thread during the load. (Remember to set a FallBack image)
Related
I am struggling with uploading an image from thew client-side to a folder on the server-side in .Net Core.I used Postman to check if the method on the server-side is working and it does without any problem,but when I try to upload an image from the client-side,I get an error on the server-side of type NullReferenceException:Object reference not set to an instance of an object.This is the Post method on the server-side:
[HttpPost]
public async Task Post(IFormFile file)
{
if (string.IsNullOrWhiteSpace(_environment.WebRootPath))
{
_environment.WebRootPath = Path.Combine(Directory.GetCurrentDirectory(), "wwwroot");
}
var uploads = Path.Combine(_environment.WebRootPath, "uploads");
//var fileName = file.FileName.Split('\\').LastOrDefault().Split('/').LastOrDefault();
if (!Directory.Exists(uploads)) Directory.CreateDirectory(uploads);
if (file.Length > 0)
{
using (var fileStream = new FileStream(Path.Combine(uploads, file.FileName), FileMode.Create))
{
await file.CopyToAsync(fileStream);
}
}
}
Apparently the method is thrown where I check if the length of the file is bigger than 0.On the client-side I get error "500 internal server error" and I tried to check using the debugger where exactly the error is thrown but i can't find anything that could resemble an error of some sort.This is the API method for the client-side:
public async Task UploadPictureAsync(MediaFile image)
{
User user = new User();
string pictureUrl = "http://10.0.2.2:5000/api/UploadPicture";
HttpContent fileStreamContent = new StreamContent(image.GetStream());
// user.Picture=GetImageStreamAsBytes(image.GetStream());
fileStreamContent.Headers.ContentDisposition = new ContentDispositionHeaderValue("form-data") {FileName=Guid.NewGuid() + ".Png",Name="image"};
fileStreamContent.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
HttpClientHandler clientHandler = new HttpClientHandler();
clientHandler.ServerCertificateCustomValidationCallback = (sender, cert, chain, sslPolicyErrors) => { return true; };
using (var client = new HttpClient(clientHandler))
{
using (var formData = new MultipartFormDataContent())
{
formData.Add(fileStreamContent);
var response = await client.PostAsync(pictureUrl, formData);
if(response.IsSuccessStatusCode)
{
var result = response.Content.ReadAsStringAsync().Result;
}
}
}
}
The image is declared in the Model as byte array:
public byte[] Picture { get; set; }
Does someone understand why my POST method has this behavior since the server-side works perfectly but fails when I try to upload an image from the client-side?What I find weird though is that when i read the error and I look at the Content-Type it is "text/plain" instead of "form-data" and I have tried to set it at the MutipartFormDataContent like this:
formData.Headers.ContentType.MediaType = "multipart/form-data";
I also tried to set the MediaTypeHeaderValue on the client like this:
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/octet-stream"));
I still get the wrong content type.
I have also tried a different approach with Stream instead of MediaFile but without any luck as it did not even hit the break point in debugger mode for the response.Any help would be appreciated! :)
I have managed to find the answer finalllyyyyy!!!The problem was on the client-side as I suspected and guess what,it was all about the correct name.It turns out that since on the server side I have IFormFile file I had to change the client side to take the parameter name "file" instead of image as well so that it could work.Thank you #Jason for the suggestions as I didn't understand the error from the first place and did some debugging on the server-side to help me figure it out.
I am developing a WP 8.1 app, which contains a ListView. In each ListView items there are some text and a picture. The pictures come from a Http GET request, which I have to bind to the xaml. I have got a solution for it earlier, but I have some performance problem with it. The ListView can contain same picture multiple times, so the GetImage task is called multiple times for the the same picture as well. On a WiFi connection it is not a big problem, but with poor connection it is.
The other thing what I would like to implement is the image caching. I don't know where is the best place to store pictures while the app is running. I should store approximately 10-40 pieces pictures, and the image sizes are between 3 and 20 KB. Due to these images are not necessary after closing the application, I think I can store them in the memory, not in the storage folder.
So, what I want: download every images at once and store them while the app is running.
Here is the code what I use to download images:
public class WebPathToImageConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, string language)
{
if (value == null) return null;
return new TaskCompletionNotifier<BitmapImage>(GetImage((string)value));
}
public object ConvertBack(object value, Type targetType, object parameter, string language)
{ throw new NotImplementedException(); }
private async Task<BitmapImage> GetImage(string emailaddress)
{
ApplicationDataContainer localSettings = ApplicationData.Current.LocalSettings;
Uri uri = new Uri((string)localSettings.Values["Server"] + "Image/Downloadavatar?EmailAddress=" + emailaddress + "&Size=NORMAL");
HttpClient webCLient = new HttpClient();
IInputStream responseStream = await webCLient.GetInputStreamAsync(uri);
MemoryStream memoryStream = new MemoryStream();
Stream stream = responseStream.AsStreamForRead();
await stream.CopyToAsync(memoryStream);
memoryStream.Position = 0;
BitmapImage bitmap = new BitmapImage();
await bitmap.SetSourceAsync(memoryStream.AsRandomAccessStream());
return bitmap;
}
}
Well I asked a similar question on regards of how to work with caching data downloading and performing them in parallel.
Take a look at the answer here: Task caching when performing Tasks in parallel with WhenAll
So in short your GetImage should go in a list that holds the tasks instead of the result.
I have a URL that is shown below:
URL is taken out due to contract reasons
WebClient webClient = new WebClient();
Uri uri = new Uri("http://www.URLhere.aspx?stopid=4556");
webClient.OpenReadCompleted += new OpenReadCompletedEventHandler
(webClient_OpenReadCompleted);
webClient.OpenReadAsync(uri);
I need to find a way to alter the end part, so change 4556 from a text block, into another text so that when the application send the request it finds the whole lot.
I thought you could do this:
WebClient webClient = new WebClient();
Uri uri = new Uri("http://www.URLhere.aspx?stopid=" + stopId);
webClient.OpenReadCompleted += new OpenReadCompletedEventHandler
(webClient_OpenReadCompleted);
webClient.OpenReadAsync(uri);
How does one do this?
Edit:
When i do the code above it returns as a null reference, so i am asuming it's not getting the text in the textbox.
It sounds like you're missing the encoding of your variable.
var myvar = "the simpsons";
Uri myUri = new Uri("http://www.URLhere.aspx?stopid=" + HttpUtility.UrlEncode(myvar));
See HttpUtility.UrlEncode Method - MSDN
there is no difference between
Uri uri = new Uri("http://www.URLhere.aspx?stopid=4556");
and
Uri uri = new Uri("http://www.URLhere.aspx?stopid=" + stopId);
so i really don't know whats your problem
Henry,
If I understand you question correctly, I think you want to append the value in a TextBox (not a TextBlock) to the URI. If that is correct and you're employing MVVM, you could bind your TextBox to a public property on the ViewModel (lets call it TextBoxProp)
private string _textBoxProp;
public string TextBoxProp
{
get{return _textBoxProp;}
set
{
_textBoxProp = value;
RaisePropertyChanged("TextBoxProp");
}
}
and then create your URI as follows:
Uri uri = new Uri(String.Format("http://www.URLhere.aspx?stopid={0}", TextBoxProp));
Be sure when you bind to the property in XAML that you set the mode to TwoWay.
I hope that helps
I am using the Background Transfer to upload Photographs to my Web Service. As the Photograph uploads can consume significant time and memory, I thought it might be a nice idea to use the background transfer request to accomplish this. After the photo is uploaded, I want to obtain the Id of the uploaded photo and then use it for post-processing. However, it turns out I can't do that in a background transfer request.
Per my understanding, Background Transfer works using the following logic ONLY:
You have to obtain the file you want to upload and then save/copy it to your app's Isolated Storage under the folder: shared/transfers. This is extremely important. Apparently, using file in a different location didn't work for me. Maybe it isn't the shared/transfers as much as it is a 'relative' path. But I would stick to the same conventions.
After you have saved the file in that location, your background request can be created based on that. It doesn't look like you can pass POST CONTENT other than the file contents, so any other parameters like file name, mime type etc. will need to be passed as QUERY String parameters only. I can understand this, but it would've been nice if I could pass both as POST Content. I don't think HTTP has a limitation on how this works.
Here is some code for creating a request using Hammock:
string url = App.ZineServiceAuthority + "articles/save-blob?ContainerName={0}&MimeType={1}&ZineId={2}&Notes={3}&IsPrivate={4}&FileName={5}";
url = String.Format(url, userId, "image/jpg", ZineId, txtStatus.Text, true, UploadFileName);
var btr = new BackgroundTransferRequest(new Uri(url, UriKind.Absolute));
btr.TransferPreferences = TransferPreferences.AllowCellularAndBattery;
btr.Method = "POST";
btr.Headers.Add("token", IsolatedStorageHelper.GetTravzineToken());
btr.UploadLocation = new Uri(#"/shared\transfers/" + UploadFileName, UriKind.Relative);
btr.TransferStatusChanged += new EventHandler<BackgroundTransferEventArgs>(btr_TransferStatusChanged);
btr.TransferProgressChanged += new EventHandler<BackgroundTransferEventArgs>(btr_TransferProgressChanged);
BackgroundTransferService.Add(btr);
In my case, I am literally passing all the necessary parameters using the query string. On a successful save, my Web Service returns back the Id of the Photo I just uploaded. However:
There is NO way (or at least I know of) to obtain and evaluate the RESPONSE. The Background Transfer Request Event handlers do not expose a RESPONSE.
Here are my event handlers:
void btr_TransferProgressChanged(object sender, BackgroundTransferEventArgs e)
{
bool isUploading = e.Request.TotalBytesToSend > 0 ? true : false;
lblStatus.Text = isUploading ? "Uploading" + e.Request.BytesSent.ToString() + " sent" : "Done";
}
void btr_TransferStatusChanged(object sender, BackgroundTransferEventArgs e)
{
if (e.Request.TransferStatus == TransferStatus.Completed)
{
using (IsolatedStorageFile iso =
IsolatedStorageFile.GetUserStoreForApplication())
{
if (iso.FileExists(e.Request.UploadLocation.OriginalString))
iso.DeleteFile(e.Request.UploadLocation.OriginalString);
}
BackgroundTransferService.Remove(e.Request);
if (null != e.Request.TransferError)
{
MessageBox.Show(e.Request.TransferError.Message);
}
else
{
lblStatus.Text = "Done baby done";
}
}
}
So now my question is, how does anyone do any sort of POST Processing in such scenarios?
Can anyone please tell me the line of thought behind designing such an inflexible class?
Any thoughts on how I could get around this issue would be appreciated.
Also, does anyone have any working examples of a homegrown BackgroundTransfer?
Haven't tried it but why not set a download location like this:
btr.DownloadLocation = "myDownloadFile.html";
btr.UploadLocation = "myUploadFile.jpg";
...
If the request is completed read the file "myDownloadFile.html" where your response has been stored and delete it afterwards.
For connecting to webservices i wrote the following code.
WebClient wc = new WebClient();
wc.DownloadStringAsync(new Uri("http://www.Webservices.asmx"));
wc.DownloadStringCompleted += new DownloadStringCompletedEventHandler(wc_DownloadStringCompleted);
void wc_DownloadStringCompleted(object sender,DownloadStringCompletedEventArgs e)
{
Debug.WriteLine("Web service says: " + e.Result);
using (var reader = new StringReader(e.Result))
{
String str = reader.ReadToEnd();
}
}
by using above code Get the string result.But i want get the result in HTMLVisulaizer then i know the what are the methods having that webservice.then i can easily access the particular method.
Please tell me how to call a web service method in Windows phone 7?in webservice i am having 5 webmethods.how to get that and how to call the Particular webmenthod.
Please tell me thanks in advance.
#venkateswara Are you talking about obtaining a list of known WebReference methods so you know which one to call in you code? Do you not see the this of known method calls when you add the WebReference to your WP7 project? Since you will be developing the WP7 app in VS I can't see the reason you would want to do this. Even if you don't own the webservice yourself, you will need to connect to it from VS in order to add the reference to your project.
Below is the screen in VS2010 where a WebReference is added. The Operations are listed on the right.
Once added you can use the ObjectBrowser to understand how the methods should be called.
Please let me know if I have missed something from your question.
#Jason James
The first step:
You must add referent Services ,like Jason James has very detailed instructions .
step 2 :
You can open App.xaml.cs , in Functions Apps
public Apps()
{
// Global handler for uncaught exceptions.
UnhandledException += Application_UnhandledException;
// Show graphics profiling information while debugging.
if (System.Diagnostics.Debugger.IsAttached)
{
// Display the current frame rate counters.
Application.Current.Host.Settings.EnableFrameRateCounter = true;
// Show the areas of the app that are being redrawn in each frame.
//Application.Current.Host.Settings.EnableRedrawRegions = true;
// Enable non-production analysis visualization mode,
// which shows areas of a page that are being GPU accelerated with a colored overlay.
//Application.Current.Host.Settings.EnableCacheVisualization = true;
}
// You can declare objects here that you will use
//Examlpe: NameservicesReferent.(Function that returns services) = new NameservicesReferent.(Function that returns services)();
Ws_Function = new Nameservices.ServiceSoapClient();
}
step 3:
in Mainpage.xaml.cs
GlobalVariables.Ws_advertise.getLinkAdvertiseIndexCompleted += new EventHandler<advertise.getLinkAdvertiseIndexCompletedEventArgs>(Ws_advertise_getLinkAdvertiseIndexCompleted);
GlobalVariables.***NameWedservise***.getLinkAdvertiseIndexAsync("**parameters to be passed**");
step 4:
void Ws_advertise_getLinkAdvertiseIndexCompleted(object sender, advertise.getLinkAdvertiseIndexCompletedEventArgs e)
{
//function returns the results to you, the example here is an array
string[] array = null;
try
{
array = e.result;
if(array != null)
}
cath(exception ex)
{
}
finally
{
array = null;
GlobalVariables.Ws_advertise.getLinkAdvertiseIndexCompleted -= new EventHandler<advertise.getLinkAdvertiseIndexCompletedEventArgs>(Ws_advertise_getLinkAdvertiseIndexCompleted);
}
}