ImageListStreamer

Implementation of the ImageList control

Problem

Working on the implementation of the ImageList, we encounter the issue of management of resources through the ImageListStreamer. The ImageListStreamer is basically a serializer of all the images that are stored inside the ImageList component.

This ImageListStreamer is initialized by the .resx file associated with the .designer in which the ImageList is created. The .rex is the one that created the instance of the ImageListStreamer, serialized in base64 all the images and associated the data with a specific public token and the System.Windows.Forms.ImageListStreamer class.

This makes it very difficult to use this data to serialize out of the implementation of the WindowsForm component because it always needs the .dlls hashes to validate the information. This means that any custom implementation of the ImageListStreamer out of WindowsForm will fail when it tries to convert or deserialize the information storage in the .resx file.

Work around

As a way to interpret this mechanism through the resource, we manage to find a work-around that uses the same resource to get every image and storage in the ImageList array. Basically, the ImageList creates an instance of the ImageListStreamer and inside this, creates a method that takes the resource as a parameter and, having stored the keys for every image, gets the object Image associated with the key.

The problem with this solution is that it needs changes in the migrated code like the call of this method that fills the ImageCollection or adds every Image manually to the .resx file and associates that image name to the key so the resource can find it when it is searched.

Possible Solutions

A possible way to manage this issue is to create a pre-serializer that changes the values that reference the System.Windows.Form.ImageListStreamer for our implementation. That might let us create an instance that references the ImageStream in the .resx file and serialize normal inside the Blazor.ImageListStreamer.

Another solution is to somehow decode the images inside the ImageStream and storage separate in the .resx files of the migration project. This will help us with the work-around to minimize the manual changes in case the first solution does not work.