Ffimageloading: System.ArgumentNullException: Value cannot be null.

[guiwaltricke]

Hello, we are using FFImageLoading in a PCL Project and sometimes the FFImageLoading throw this exception: "System.ArgumentNullException: Value cannot be null"

this is the only stack that the problem gives to us....

<forms:CachedImage HorizontalOptions="Start"
                                   VerticalOptions="Center"
                                   WidthRequest="50"
                                   HeightRequest="50"
                                   DownsampleWidth="50"
                                   DownsampleHeight="50"
                                   DownsampleToViewSize = "true"
                                   Source="{Binding MyImage">

 <forms:CachedImage.Transformations>
     <transformations:CircleTransformation />
  </forms:CachedImage.Transformations>
</forms:CachedImage>

what we saw here is that when we are not using CircleTransformation the error is seems to not appear again...

thanks

[daniel-luberda]

Somehow, memory cache entries with null cache key are being added. Could you run it with verbose logging to debug when exactly it occurs (for which urls/images)? Something like that:

``` C#
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
FFImageLoading.Forms.Droid.CachedImageRenderer.Init();

        var config = new FFImageLoading.Config.Configuration()
        {
            VerboseLogging = true,
            VerbosePerformanceLogging = false,
            VerboseMemoryCacheLogging = false,
            VerboseLoadingCancelledLogging = false,
            Logger = new CustomLogger(),
        };
        ImageService.Instance.Initialize(config);

        global::Xamarin.Forms.Forms.Init(this, bundle);
        LoadApplication(new App());
    }

    public class CustomLogger : FFImageLoading.Helpers.IMiniLogger
    {
        public void Debug(string message)
        {
            Console.WriteLine(message);
        }

        public void Error(string errorMessage)
        {
            Console.WriteLine(errorMessage);
        }

        public void Error(string errorMessage, Exception ex)
        {
            Error(errorMessage + System.Environment.NewLine + ex.ToString());
        }
    }

```

[LuigiMaestrelli]

We have attached the log error.
When this error occurs, the image shows, but it isn't a circle.
The transformation has not been applied.

log.txt

[daniel-luberda]

Thanks! It should be fixed with this: https://github.com/luberda-molinet/FFImageLoading/commit/073f4772ab3c4c71d2b2473691bfaff9a7149dcb

[LuigiMaestrelli]

Thanks a lot.

Any ideias about when will be a release or a prerelease with the fix?

[daniel-luberda]

FFImageLoading 2.1.8-pre-146 nuget which contains discussed fixes released.

[LuigiMaestrelli]

The exception is no longer happening.
But a single image on the ListView isn't a circle.
The image with the error changes each time I start the app.

[daniel-luberda]

• Is it always the same image?
• What is its source? Is it a local file / url?
• The important thing is to set Transformations property before Source property.

[LuigiMaestrelli]

No, it isn`t the same image.
The source is a local ImageSource
This is how I use the component on a ViewCell

                  <forms:CachedImage HorizontalOptions="Start"
                                     VerticalOptions="Center"
                                     WidthRequest="50"
                                     HeightRequest="50"
                                     DownsampleWidth="50"
                                     DownsampleHeight="50"
                                     DownsampleToViewSize = "true"
                                     Source="{Binding Imagem}, Mode=OneWay}">

                    <forms:CachedImage.Transformations>
                      <transformations:CircleTransformation />
                    </forms:CachedImage.Transformations>

                  </forms:CachedImage>

[daniel-luberda]

Source="{Binding Imagem}, Mode=OneWay} should be Source="{Binding Imagem, Mode=OneWay}

[LuigiMaestrelli]

Yes, is coded that way.
Sorry, I was testing something else.

                  <forms:CachedImage HorizontalOptions="Start"
                                     VerticalOptions="Center"
                                     WidthRequest="50"
                                     HeightRequest="50"
                                     DownsampleWidth="50"
                                     DownsampleHeight="50"
                                     DownsampleToViewSize = "true"
                                     Source="{Binding Imagem, Mode=OneWay}">

                    <forms:CachedImage.Transformations>
                      <transformations:CircleTransformation />
                    </forms:CachedImage.Transformations>

                  </forms:CachedImage>

[daniel-luberda]

Could you try this:

``` C#
VerticalOptions="Center"
WidthRequest="50"
HeightRequest="50"
DownsampleWidth="50"
DownsampleHeight="50"
DownsampleToViewSize = "true">

<forms:CachedImage.Transformations>
  <transformations:CircleTransformation />
</forms:CachedImage.Transformations>

<forms:CachedImage.Source>
    <Binding Path="Imagem"/>
</forms:CachedImage.Source>

```

?

[LuigiMaestrelli]

That worked, I can no longer simulate behavior.
Thank you.

[daniel-luberda]

I fixed this with: https://github.com/luberda-molinet/FFImageLoading/commit/272c51f994803598673cbf72f7fb8abba4726bd4. It will prevent such behavior in future.

[daniel-luberda]

2.1.8-pre-150 released. It will allow your previous code to work correctly without any modifications. Could you check it?