WPF WeakReference

Install-Package MessagePack
Install-Package Newtonsoft.json

 

public class ImgUrlToImgSourceConverter : IValueConverter
{
    Dictionary<string, WeakReference<BitmapImage>> imgCache = new Dictionary<string, WeakReference<BitmapImage>>();
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        try
        {
            string? imgUrl = value?.ToString();
            if (!string.IsNullOrEmpty(imgUrl) && File.Exists(imgUrl))
            {
                if (imgCache.TryGetValue(imgUrl, out var weakRef) && weakRef.TryGetTarget(out var cachedImg))
                {
                    return cachedImg;
                }
                BitmapImage bmi = new BitmapImage();
                bmi.BeginInit();
                bmi.UriSource = new Uri(imgUrl, UriKind.RelativeOrAbsolute);
                bmi.CacheOption = BitmapCacheOption.OnDemand;
                bmi.CreateOptions = BitmapCreateOptions.DelayCreation;
                bmi.EndInit();
                if (bmi.CanFreeze)
                {
                    bmi.Freeze();
                }
                imgCache[imgUrl] = new WeakReference<BitmapImage>(bmi);
                return bmi;
            }
            return null;
        }
        catch (Exception ex)
        {
            return null;
        }
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2026-03-29T22:13:36.6861304+08:00,start:0,end:49999999,batch size:1000000,batch_count:51
'WpfApp9.exe' (CoreCLR: clrhost): Loaded 'C:\Program Files\dotnet\shared\Microsoft.NETCore.App\10.0.4\System.Numerics.Vectors.dll'. Skipped loading symbols. Module is optimized and the debugger option 'Just My Code' is enabled.
'WpfApp9.exe' (CoreCLR: clrhost): Loaded 'D:\C\WpfApp9\WpfApp9\bin\Debug\net10.0-windows\Newtonsoft.Json.dll'. Skipped loading symbols. Module is optimized and the debugger option 'Just My Code' is enabled.
'WpfApp9.exe' (CoreCLR: clrhost): Loaded 'C:\Program Files\dotnet\shared\Microsoft.NETCore.App\10.0.4\System.Runtime.Numerics.dll'. Skipped loading symbols. Module is optimized and the debugger option 'Just My Code' is enabled.
'WpfApp9.exe' (CoreCLR: clrhost): Loaded 'C:\Program Files\dotnet\shared\Microsoft.NETCore.App\10.0.4\System.Linq.Expressions.dll'. Skipped loading symbols. Module is optimized and the debugger option 'Just My Code' is enabled.
'WpfApp9.exe' (CoreCLR: clrhost): Loaded 'C:\Program Files\dotnet\shared\Microsoft.NETCore.App\10.0.4\System.Data.Common.dll'. Skipped loading symbols. Module is optimized and the debugger option 'Just My Code' is enabled.
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