title: Using FRP (and immutable collections) with many objects, shown on a grid
body: <p>I've been reading about FRP lately and really liked the idea so far. There are a couple of things I haven't found much information about, and one of them is this: If I use, for example, a WPF grid for displaying my data (with some thousands of rows), how should I wire the updates to the grid?</p>
  
  <p>I should note that I have relatively little experience with WPF too, but as far as I understand, this would usually be solved by binding the grid to an <code>ObservableCollection&lt;T&gt;</code>, which, if I understand correctly, is very good at handling the updates (meaning updating, adding or removing single items is handled with good performance).</p>
  
  <p>So then, if I wanted to use FRP with immutable collections, this isn't applicable. But what other options are there? If I re-fill the whole grid with each and every update, add or delete, I would guess the performance is quite appalling.</p>
  
  <p>I also don't really have example code to show because, frankly, this is such a basic thing that I wouldn't know where to start without knowing how to do this first. And while I'm specifically talking about C# and WPF in here, I'm also interested in the general principles.</p>