I am working on a C# project, and I am having a strange problem. I have an Image control and I am trying to display an image within it. There is no error or exception thrown, but the image doesn't display.
Below is the code I am using:
BitmapImage image = new BitmapImage();
image.UriSource = new Uri("images\\low_battery.png", UriKind.Relative);
imageIcon.Source = image;
imageIcon.Visibility = System.Windows.Visibility.Visible;
I have the directory image and the image file low_battery.png running in the same directory as to where the executable is running from.
Thanks for any help you can provide.
A few suggestions:
1) You can get the exception from WPF if you subscribe to the ImageFailed even on imageIcon and the and DownloadFailed event on BitmapImage. Then put breakpoints in those methods and see what it says.
2) Before setting UriSource, call image.BeginInit(). After setting UriSource, call image.EndInit(). To help debug the problem, you can subscribe to the ImageFailed event on imageIcon and DownloadFailed on BitmapImage. So the final code looks like this:
BitmapImage image = new BitmapImage();
image.BeginInit();
image.UriSource = new Uri("/images/low_battery.png", UriKind.Relative);
image.DownloadFailed += image_DownloadFailed;
image.EndInit();
imageIcon.ImageFailed += imageIcon_ImageFailed;
imageIcon.Source = image;
imageIcon.Visibility = System.Windows.Visibility.Visible;
and further down:
void imageIcon_ImageFailed(object sender, ExceptionRoutedEventArgs e)
{
// Breakpoint here
}
void image_DownloadFailed(object sender, ExceptionEventArgs e)
{
// Breakpoint here
}
3) Another way to do this is to embed images directly into your project. Do that by adding an images folder into your project, then adding the image, and setting the type to "Resource"
Either call image.BeginInit() before setting image.UriSource and image.EndInit() afterwards, or simply use the BitmapImage constructor that takes an Uri as argument:
var uri = new Uri("images\\low_battery.png", UriKind.Relative);
imageIcon.Source = new BitmapImage(uri);
Related
I'm creating BitmapImages, to download images from IP cam.
I use DownloadCompleted, DownloadFailed and DownloadProgress events.
But every hour, I reset everything. Those images are created dynamically, and I'd like to clear them (or destroy them) when I reset. But I don't find them, and they continue to fire the events....
Here the example :
void dispatcherTimer_Tick(object sender, EventArgs e)
{
BitmapImage img = New BitmapImage();
img.BeginInit();
img.CacheOption = BitmapCacheOption.None;
img.UriCachePolicy = new RequestCachePolicy(RequestCacheLevel.NoCacheNoStore);
img.CreateOptions = BitmapCreateOptions.IgnoreImageCache;
img.DownloadCompleted += DownloadCompleted;
img.DownloadFailed += DownloadFailed;
img.DownloadProgress += bi_DownloadProgress;
img.UriSource = new Uri(xR["URLJPG"].ToString());
//xR["URLJPG"] is a DataViewRow, that contains the url to download for each image)
img.EndInit();
}
There is several images created this way. I'd like to clear ou destroy them all.
So i have this code which for every string in the array it adds it the file path and uses it as the file path for the image box, this is the code:
private async void Button7_Click(object sender, RoutedEventArgs e)
{
string[] images = new string[] { "Star_00001.png", "Star_00002.png", "Star_00003.png", "Star_00004.png", "Star_00005.png", "Star_00006.png", "Star_00007.png", "Star_00008.png"};
string path = "Assets/Star/";
foreach(string file in images)
{
string thepath = Path.Combine(path,file);
await Task.Delay(46);
BitmapImage Image = new BitmapImage();
Image.UriSource = new Uri(this.BaseUri, thepath);
StarImage.Source = Image;
}
}
Now everytime the new image is loaded in to the StarImage, it flickers, as far as I know their is no way to stop this because it is the effect of loading a new image in the image box, however does anyone know any alternatives to stop this and give the effect of an animation?
I think some sort of buffering technique may reduce or eliminate the flickering problem you have.
I've never done this in c#, but essentially you draw to an image which is not yet visible referred to as the buffer, and then make it visible when the image is completely drawn.
This may help.
try this:
private async void Button7_Click(object sender, RoutedEventArgs e)
{
string[] images = new string[] { "Star_00001.png", "Star_00002.png", "Star_00003.png", "Star_00004.png", "Star_00005.png", "Star_00006.png", "Star_00007.png", "Star_00008.png" };
string path = "Assets/Star/";
foreach (string file in images)
{
string thepath = Path.Combine(path, file);
await Task.Delay(46);
BitmapImage Image = new BitmapImage();
Image.BeginInit();
Image.UriSource = new Uri(this.BaseUri, thepath);
Image.CacheOption = BitmapCacheOption.OnLoad;
Image.EndInit();
StarImage.Source = Image;
}
}
I've been racking my brains for months trying to solve this, and then I found this post. It helped me solve this! I can't understand for the life of me why Microsoft keeps changing the syntax to do things in windows.
How to set Background of a Button without flicker?
I have an issue that I think has not been covered in the multitude of other WPF image loading issues. I am scanning in several images and passing them to a "Preview Page". The preview page takes the image thumbnails and displays what a printout would look like via a generated bitmap.
The weird thing to me is, it will work fine if I run the program the first time. Upon reaching the end of the process and hitting "start over", the preview will return blank. I am creating the BitmapImage in a method that saves the bitmap as a random file name so I do not believe theres a lock on the file the second time around. Also, if I go to look at the temporary file created through explorer, it is drawn correctly so I know the appropriate data is getting to it.
Finally, when I navigate away from this page, I am clearing necessary data. I'm really perplexed and any help would be appreciated.
//Constructor
public Receipt_Form() {
InitializeComponent();
printData = new List<Object>();
this.Loaded += new RoutedEventHandler(MainWindow_Loaded);
}
void MainWindow_Loaded(object sender, RoutedEventArgs e) {
// populates global variable fileName
var task = System.Threading.Tasks.Task.Factory.StartNew(() => outputToBitmap()); task.ContinueWith(t => setImage(fileName),
System.Threading.Tasks.TaskScheduler.FromCurrentSynchronizationContext());
// I started the image creation in a separate thread because I
// thought it may be blocking the UI thread, but it didn't matter
}
private void setImage(string imageURI) {
BitmapImage image;
using (FileStream stream = File.OpenRead(imageURI)) {
image = new BitmapImage();
image.BeginInit();
image.StreamSource = stream;
image.CacheOption = BitmapCacheOption.OnLoad;
image.EndInit();
}
receiptPreview.Source = image;
//this works the first iteration but not the second, though the temp file is created successfully
}
Found the issue - the Modern UI container was getting cleared when transitioning off the page.
I want to show an image from Disk !
private void Button_Click_3(object sender, RoutedEventArgs e)
{
myImage.Source = new BitmapImage(
new Uri("images\\Countries\\dz.png",UriKind.Relative));
}
I'm sure that the filename is correct but
when I press the button, The image doesn't appear, I also made sure that the image is in the front of all other control and that myImage is its name .
Try this:
private void Button_Click_3(object sender, RoutedEventArgs e)
{
try
{
myImage.Source = new BitmapImage(
new Uri(#"images\Countries\dz.png",UriKind.Relative));
}
catch(Exception ex)
{
MessageBox.Show(ex.Message);
}
}
Putting # makes it a literal string (you don't need to provide
escape sequence then)
If the above also doesn't work then it'll show the exception if any
occurs.
BitmapImage bitImg = new BitmapImage();
bitImg.BeginInit();
bitImg.UriSource = new Uri("images\\Countries\\dz.png", UriKind.Relative);
bitImg.EndInit();
myImage.Source = bitImg;
A few things that may help you:
Instead of:
myImage.Source = new BitmapImage(new Uri("images\\Countries\\dz.png",UriKind.Relative));
Try This:
BitmapImage ImageName = new BitmapImage;
ImageName.BeginInit();
ImageName.UriSource = new Uri(#"images\Countries\dz.png",UriKind.Relative);
ImageName.EndInit();
myImage.Source = ImageName;
See below link (examples section at the bottom of the page) for more info.
http://msdn.microsoft.com/en-us/library/system.windows.media.imaging.bitmapimage.aspx
If the above doesn't work, we will need you to post more code :). Also, it would help if you specify exactly what you are trying to achieve here.
Try to Debug it.
Put a break point on the line(F9) and hit F5 to start debugging. Check the value of myImage.Source after the line is executed (F10 to step).
You can also use the Immediate Window to test other statements while debugging is paused and see the results.
Also make sure that the images folder is in the same folder as the executable file (in Debug or Release folders, according to your build)
If I've got a Silverlight Image control that downloads from a full URL, how can I get the size (in bytes) of the downloaded image without making another web call?
I can't find anything on the Image or the BitmapImage source behind it that would tell me. And even the DownloadProgress event on the BitmapImage only gives a percentage.
I never noticed it before, but that is kind of a strange gap in the framework...
You'll probably have to download the image by itself using a WebClient object. That'll give you a stream of bytes. You can check the length of the stream, and then create a bitmap from the stream.
Code to set up the web client and begin the download (note, it's an async call, so we assign an event handler to fire when it completes the download.)
WebClient wc = new WebClient();
wc.OpenReadCompleted += new OpenReadCompletedEventHandler(wc_OpenReadCompleted);
Uri someImageUri = new Uri("http://www.somesite.com/someimage.jpg");
wc.OpenReadAsync(someImageUri);
Here's an example of what the event handler method might look like:
void wc_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
{
System.IO.Stream imageStream = e.Result;
long imageSize = imageStream.Length;
BitmapImage bi = new BitmapImage();
bi.SetSource(imageStream);
Image image = new Image();
image.Source = bi;
}
Obviously, if you already have an image control on your form, you wouldn't need to create a new one, or if you did want to create it, you'll have to add it to a parent panel of some kind...
~Chris