[Blazor] API for interpreting RenderFragment contents.

[javiercn]

The idea is to allow interpreting a render fragment so that it can be transformed to change it before applying it.

[mrpmorris]

Cos you give a mock-up example of this, please! Thanks @javiercn

[Postlagerkarte]

Great! For what it is worth here are two more supporting issues for this:

#9493
#16737

[mrlife]

Related: #29648

[tstockwell]

The idea is to allow interpreting a render fragment so that it can be transformed to change it before applying it.

Seems like this would be possible right now...

// the original render fragment
void OriginalRenderFragment(RenderTreeBuillder builder) {
      // some rendering logic here
}

// a new render fragment that applies customizations to the output from OriginalRenderFragment
void RenderWithTransformations(RenderTreeBuillder builder) {
      var builder1= new RenderTreeBuilder();
      OriginalRenderFragment(builder1);
      var frames1= builder1.GetFrames();
      
      var frames2= ApplyMyTransformations(frames1);   
      RenderFrames(builder, frames2); 
}

// applies some transformations to an array of frames and returns a new array
ArrayRange<RenderTreeFrame> ApplyMyTransformations(ArrayRange<RenderTreeFrame> frames) {
       .....
}

// simply renders the given frames to a RenderTreeBuilder
void RenderFrames(RenderTreeBuilder builder, ArrayRange<RenderTreeFrame> frames) {
    ....
}

I'm aware that frames belong to an internal package, that's not a showstopping problem for me, but it would be nice if Blazor had a legit API that let me do something equivalent to this.

[Hecatron]

I recently ran into this problem with - #36976
One question is if there is a way to add an existing frame to a builder, since I didn't see an API for that
with the above this would be the part within RenderFrames

The way I've fudged it myself so far is to

// Add a dummy entry to the destination array in the builder, this increments the count
destbuilder.AddMarkupContent(i, "");

// Do a direct assign to the array to overwrite the struct.
var destframes = destbuilder.GetFrames();
destframes.Array[i] = srcframes.Array[i];

I'm sure this isn't right but for now it does work. Ideally we need an API for copying / assigning an existing frame from a different Array of frames.

[ghost]

We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our Triage Process.

[ghost]

We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our Triage Process.

[macias]

I can see this ticket is swallowing others, and from developer perspective it is a problem, because I fear the scope of this particular issue is so grand it will take more years to accomplish (and this is not set in stone it will ever be). And the swallowed posts are more focused, and I believe more probable to support right now. I am pointing at supporting collection of RenderFragment (currently there are workarounds for it, but AFAIK not proper solutions).

So writing this from 2024 perspective, 5 years passed and there is still no basic collection support because it could not be done in this time no matter what, or there is no support because we keep aiming higher and this is what kills collection support? If it the latter case, IMHO it would be much better to split those issues and allow a separate ticket for collection support.