UWP：当没有可用的 Inte.net 时设置 ImageSource 时出现问题

Question

I have a scenario where I have UI which has a dropdown and an image. This UI shows the first item(Item A) in the dropdown selected which shows Image A on the UI. When this UI shows up first the inte.net is disconnected. I still see Image A. Now I try to select another item from the dropdown Item B and this time I don't see Image B.

This is how I set the Image Source

UI:

<Image source= "{x:bind Viewmodel.SampleImage}, mode=OneWay">
</Image>

Backend:

private ImageSource sampleImage;
public ImageSource SampleImage
{
   get => this.sampleImage;
   set => this.SetProperty(ref this.sampleImage, value);
 }

public void Initialize()
{
   // Everytime I change my selection from the dropdown this function is triggered which tries to set the value of Image displayed in the UI
    BitmapImage fallbackImage = new BitmapImage(new Uri("https://randomImage"));
    this.SampleImage = fallbackImage;
 }

I need help in understanding why the second image Image B does not show up when the inte.net is disconnected here.And how do I handle this case when the inte.net is disconnected and I need to still display the image if I don't have local fallback images.

Answer 1

Based on the code you share, the Initialize method will only be triggered when the dropdown selection is changed, so the image is actually downloaded only when the item is selected.

When you disconnect from the inte.net, the download action will fail. The image B will not be show because the image is not downloaded. The reason why image A still should is that the BitmapImage will cache the image it uses before.