UWP bound image not updating

Question

I have an image bound to my viewmodel

<Image x:Name="imgNew" Source="{x:Bind Pvm.NewBitmap}" />

I do an initial load of the image in the viewmodel

        fileStream = await file.OpenAsync(FileAccessMode.Read);
        try
        {
            fileStream.Seek(0);
            NewBitmap.SetSource(fileStream);
        }

    private WriteableBitmap _NewBitmap;
    public WriteableBitmap NewBitmap
    {
        get { return _NewBitmap; }
        set
        {
            if (value != _NewBitmap)
            {
                _NewBitmap = value;
                RaisePropertyChanged("NewBitmap");
            }
        }
    }

This shows the image on my page

I am then doing some rendering using the Lumia Imaging library to change the NewBitmap which I want to be reflected in the page but it doesn't change.

The Property change event fires but the change doesn't show until I move away to do something like resizing the app.

Is there a way for the image to be updated though binding?

Answer 1

Looks like I have found the answer, I needed to do NewImage.Invalidate();

https://learn.microsoft.com/en-us/previous-versions/windows/silverlight/dotnet-windows-silverlight/dd491176(v=vs.95)

Answer 2

Hello,

Welcome to Microsoft Q&A!

Currently, Microsoft Q&A supports the products listed over here: supported topics (more to be added later on).

I noticed that you are using X:Bind markup in your code. The default binding mode of X:Bind is one-time. You could override the default mode of X:Bind to one-way or two-way in your code.

Like this:

<Image x:Name="imgNew" Source="{x:Bind NewBitmap, Mode=OneWay}"/>  

For more information about data binding mode, you could go through this document: Data binding in depth

Thank you.

---

If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Answer 3

Hi

Ok, I have done some changes to the code and listed it below, it works the first time now but if I do a revert then apply another effect NewBitmap is not updated, the values are the same, however, if I then resize the page slightly the image is updated.

Reset Code
filterEffects.Clear()
fileStream.Seek(0);
NewBitmap.SetSource(fileStream);
fileStream.Seek(0);
OriginalBitmap.SetSource(fileStream);
fileStream.Seek(0);
Renderer = new WriteableBitmapRenderer
{
RenderOptions = RenderOptions.Mixed,
OutputOption = OutputOption.PreserveAspectRatio,
WriteableBitmap = OriginalBitmap,
Source = new RandomAccessStreamImageSource(fileStream)
};

Imaging Library Set Effect

filterEffects.Add(new GrayscaleEffect(Renderer.Source));
WriteableBitmapRenderer l_render = new WriteableBitmapRenderer();
l_render.WriteableBitmap = OriginalBitmap;
l_render.RenderOptions = RenderOptions.Mixed;
l_render.Source = filterEffects;
NewBitmap = await l_render.RenderAsync();
Renderer.Source = l_render.Source;
await Renderer.RenderAsync();