I can't figure out at all how to create an ImageSource from a base64 string.
let source = new ImageSource();
source.fromBase64('b64strhere').then(..);
in this context the parameter passed in the following promise is a boolean which I don't know what's supposed to represent. The ImageSource afterwards is null both on android and iOS.
What am I missing here?
I load it and put in an Image element like this:
this.imageSource = new ImageSource();
var loadedBase64 = this.imageSource.loadFromBase64(MY_BASE_64_STRING_PREVIOUSLY_SAVED);
console.log(loadedBase64);
if (loadedBase64) {
let photo = <Image>this.photoImage.nativeElement;
photo.imageSource = this.imageSource;
this.photo = photo;
}
(NS 3.1)
Related
I'm new to Xamarin. I'm trying display a list of downloaded images. I am downloading images from an APP API on Azure, where I stored the file on Azure Storage.
My server code is the following:
public HttpResponseMessage Get(string PK, string RK)
{
//Creating CloudBlockBlolb...
byte[] bytes = new byte[blockBlob.Properties.Length]
for(int i = 0; i < blockBlob.Properties.Length; i++){
bytes[i] = 0x20;
}
blockBlob.DownloadToByteArray(bytes, 0);
HttpResponseMessage resp = new HttpResponseMessage(HttpStatusCode.OK);
resp.Content = new ByteArrayContent(bytes);
resp.Content.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue("image/jpg");
return resp;
}
My Xamarin code is the following:
public MainPage ()
{
//...
List<PicturePost> list = new List<PicturePost>{
new PicturePost("title", "subtitle", "link/api/Pictures?PK=xxx&RK=yyy")
};
InitializeComponent ();
listView.ItemTemplate = new DataTemplate (typeof(CustomImageCell));
listView.HasUnevenRows = true;
listView.ItemsSource = list;
//...
}
And here is the relevant code for CustomImageCell:
var image = new Image ();
image.SetBinding (Image.SourceProperty, "image");
//...
horizontalLayout.Children.Add (image);
I know that my API call works, because when I test it on the browser, it returns the image. I also know that if I use any random links such as http://www.natureasia.com/common/img/splash/thailand.jpg the image is downloaded and displayed properly. It is only when I use the API link that it doesn't seem to be working. Can someone tell me what I am doing wrong?
so in my public MainPage(), I added the following:
listView.BeginRefresh ();
listView.EndRefresh ();
I realized at some point that the images would take some time to download. I assume that when the listView was created, the images were not finished downloading, so I added the code above... Pretty sure this is not the best way to do this (probably an await would be better, but I don't know where).
I want to user sting in another class so if you know how to use? please help me.
I am using below link but it did't work for me. it return nil or fatal error.
How to call another method from another class in swift?
below code:
var objSymbol = SymbolListVC()
code = objSymbol.code
selectedMarket = objSymbol.SMarket
below Code of Symbol class:I am gating the value in code and skt
var Skt: String!
var code: String!
code = sbol?["Code"] as? String
Skt = sbol?["kt"] as? String
Thank You.
Does SymbolListVC.code have an initial value? Or do you mean to use an existing object of SymbolListVC and read the value of code from there?
Ideally, you should be using if directives if you are not certain that a variable will have a value
if let code = objSymbol.code {
//Do your processing here
}
But before that, assuming you want to use an existing instance of SymbolListVC, your code will create a new object of the class. So you might want to change that part.
var valueToPass:String!
func tableView(tableView: UITableView!, didSelectRowAtIndexPath indexPath: NSIndexPath!) {
println("You selected cell #\(indexPath.row)!")
// Get Cell Label
let indexPath = tableView.indexPathForSelectedRow();
let currentCell = tableView.cellForRowAtIndexPath(indexPath!) as UITableViewCell!;
valueToPass = currentCell.textLabel.text
performSegueWithIdentifier("yourSegueIdentifer", sender: self)
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if (segue.identifier == "yourSegueIdentifer") {
// initialize new view controller and cast it as your view controller
var viewController = segue.destinationViewController as AnotherViewController
// your new view controller should have property that will store passed value
viewController.passedValue = valueToPass
}
}
I'm trying to write code to convert a GIF annimation file into a base64 string and then convert it from base 64 string back into an image. The code I've written is for standard image files (i.e. Bitmap, JPEG, GIF). Animated GIFs, however, are different and obviously require a different step-by-step.
Here is the code I've written for converting an image to base64 string:
if (pbTitlePageImage.Image != null)
{
// This is the step-by-step for writing an image to binary.
string Image2BConverted;
using (Bitmap bm = new Bitmap(pbTitlePageImage.Image))
{
using (MemoryStream ms = new MemoryStream())
{
BinaryWriter bw = new BinaryWriter(ms);
bm.Save(ms, ImageFormat.Jpeg);
Image2BConverted = Convert.ToBase64String(ms.ToArray());
GameInfo.TitlePageImage = Image2BConverted;
bw.Close();
ms.Close();
GameInfo.TitlePageImagePresent = true;
ProjectNeedsSaving = true;
}
}
}
And here is the code I've written for converting a base64 string back to an image:
{
byte[] TitlePageImageBuffer = Convert.FromBase64String(GameInfo.TitlePageImage);
MemoryStream memTitlePageImageStream = new MemoryStream(TitlePageImageBuffer, 0, TitlePageImageBuffer.Length);
memTitlePageImageStream.Write(TitlePageImageBuffer, 0, TitlePageImageBuffer.Length);
memTitlePageImageStream.Position = 0;
pbTitlePageImage.Image = Bitmap.FromStream(memTitlePageImageStream, true);
memTitlePageImageStream.Close();
memTitlePageImageStream = null;
TitlePageImageBuffer = null;
}
After converting the base64 string back into an image, it must be loaded into a picturebox. The above code examples will work, but only the first image in the animation chain makes it through and thus is the only part if the animation that appears in the picturebox. I need to write code that will handle the entire animation. Thanks in advance!
I found a way to solve it:
byte[] imageByte = Base64.decodeBase64(imageData.getImageBase64());
new FileOutputStream("image2.gif");
write(imageByte);
close();
I dont know why, but using a FileOutput String i could get a file with the complete animation.
When my images are being loaded from my database on my web server, I see the following error:
A generic error occurred in GDI+. at
System.Drawing.Image.Save(Stream stream, ImageCodecInfo encoder,
EncoderParameters encoderParams) at
System.Drawing.Image.Save(Stream stream, ImageFormat format) at
MyWeb.Helpers.ImageHandler.ProcessRequest(HttpContext context)
All my code is attempting to do is load the image, can anybody take a look and let me know what I'm doing wrong?
Note - This works if I test it on my local machine, but not when I deploy it to my web server.
public void ProcessRequest(HttpContext context)
{
context.Response.Clear();
if (!String.IsNullOrEmpty(context.Request.QueryString["imageid"]))
{
int imageID = Convert.ToInt32(context.Request.QueryString["imageid"]);
int isThumbnail = Convert.ToInt32(context.Request.QueryString["thumbnail"]);
// Retrieve this image from the database
Image image = GetImage(imageID);
// Make it a thumbmail if requested
if (isThumbnail == 1)
{
Image.GetThumbnailImageAbort myCallback = new Image.GetThumbnailImageAbort(ThumbnailCallback);
image = image.GetThumbnailImage(200, 200, myCallback, IntPtr.Zero);
}
context.Response.ContentType = "image/png";
// Save the image to the OutputStream
image.Save(context.Response.OutputStream, ImageFormat.Png);
}
else
{
context.Response.ContentType = "text/html";
context.Response.Write("<p>Error: Image ID is not valid - image may have been deleted from the database.</p>");
}
}
The error occurs on the line:
image.Save(context.Response.OutputStream, ImageFormat.Png);
UPDATE
I've changed my code to this, bit the issue still happens:
var db = new MyWebEntities();
var screenshotData = (from screenshots in db.screenshots
where screenshots.id == imageID
select new ImageModel
{
ID = screenshots.id,
Language = screenshots.language,
ScreenshotByte = screenshots.screen_shot,
ProjectID = screenshots.projects_ID
});
foreach (ImageModel info in screenshotData)
{
using (MemoryStream ms = new MemoryStream(info.ScreenshotByte))
{
Image image = Image.FromStream(ms);
// Make it a thumbmail if requested
if (isThumbnail == 1)
{
Image.GetThumbnailImageAbort myCallback = new Image.GetThumbnailImageAbort(ThumbnailCallback);
image = image.GetThumbnailImage(200, 200, myCallback, IntPtr.Zero);
}
context.Response.ContentType = "image/png";
// Save the image to the OutputStream
image.Save(context.Response.OutputStream, ImageFormat.Png);
} }
Thanks.
Probably for the same reason that this guy was having problems - because the for a lifetime of an Image constructed from a Stream, the stream must not be destroyed.
So if your GetImage function constructs the returned image from a stream (e.g. a MemoryStream) and then closes the stream before returning the image then the above will fail. My guess is that your GetImage looks a tad like this:
Image GetImage(int id)
{
byte[] data = // Get data from database
using (MemoryStream stream = new MemoryStream(data))
{
return Image.FromStream(data);
}
}
If this is the case then try having GetImage return the MemoryStream (or possibly the byte array) directrly so that you can create the Image instance in your ProcessRequest method and dispose of the stream only when the processing of that image has completed.
This is mentioned in the documentation but its kind of in the small print.
For some reason I need to save some big strings into user profiles. Because a property with type string has a limit to 400 caracters I decited to try with binary type (PropertyDataType.Binary) that allow a length of 7500. My ideea is to convert the string that I have into binary and save to property.
I create the property using the code :
context = ServerContext.GetContext(elevatedSite);
profileManager = new UserProfileManager(context);
profile = profileManager.GetUserProfile(userLoginName);
Property newProperty = profileManager.Properties.Create(false);
newProperty.Name = "aaa";
newProperty.DisplayName = "aaa";
newProperty.Type = PropertyDataType.Binary;
newProperty.Length = 7500;
newProperty.PrivacyPolicy = PrivacyPolicy.OptIn;
newProperty.DefaultPrivacy = Privacy.Organization;
profileManager.Properties.Add(newProperty);
myProperty = profile["aaa"];
profile.Commit();
The problem is that when I try to provide the value of byte[] type to the property I receive the error "Unable to cast object of type 'System.Byte' to type 'System.String'.". If I try to provide a string value I receive "Invalid Binary Value: Input must match binary byte[] data type."
Then my question is how to use this binary type ?
The code that I have :
SPUser user = elevatedWeb.CurrentUser;
ServerContext context = ServerContext.GetContext(HttpContext.Current);
UserProfileManager profileManager = new UserProfileManager(context);
UserProfile profile = GetUserProfile(elevatedSite, currentUserLoginName);
UserProfileValueCollection myProperty= profile[PropertyName];
myProperty.Value = StringToBinary(GenerateBigString());
and the functions for test :
private static string GenerateBigString()
{
StringBuilder sb = new StringBuilder();
for (int i = 0; i < 750; i++) sb.Append("0123456789");
return sb.ToString();
}
private static byte[] StringToBinary(string theSource)
{
byte[] thebytes = new byte[7500];
thebytes = System.Text.Encoding.ASCII.GetBytes(theSource);
return thebytes;
}
Have you tried with smaller strings? Going max on the first test might hide other behaviors. When you inspect the generated string in the debugger, it fits the requirements? (7500 byte[])
For those, who are looking for answer. You must use Add method instead:
var context = ServerContext.GetContext(elevatedSite);
var profileManager = new UserProfileManager(context);
var profile = profileManager.GetUserProfile(userLoginName);
profile["MyPropertyName"].Add(StringToBinary("your cool string"));
profile.Commit();