Invalid cross-thread access issue

Question

I have two ViewModel classes : PersonViewModel and PersonSearchListViewModel. One of the fields PersonViewModel implements is a profile image that is downloaded via WCF(cach

Answer 1

It can be achieved with WriteableBitmap.

    public void LoadThumbAsync(Stream src, 
                    WriteableBitmap bmp, object argument)  
    {  
        ThreadPool.QueueUserWorkItem(callback =>  
        {  
            bmp.LoadJpeg(src);  
            src.Dispose();  
            if (ImageLoaded != null)  
            {  
                Deployment.Current.Dispatcher.BeginInvoke(() =>  
                {  
                    ImageLoaded(bmp, argument);  
                });  
            }  
        });  
    }

But You have to construct WriteableBitmap in UI Thread, then loading can be performed in other thread.

    void DeferImageLoading( Stream imgStream )  
    {  
        // we have to give size  
        var bmp = new WriteableBitmap(80, 80);  
        imageThread.LoadThumbAsync(imgStream, bmp, this);  
    }  

See more explanaition on this blog post