Tuesday, 16 March 2004

.NET CF whinging

My major whinge is just that, where the overload count has been reduced, it's the most configurable overloads that have been dropped. Yes, this saves metadata in the runtime - but it hurts the programmer (in some cases having to avoid the framework entirely because you're boxed in). The original designers of Windows CE got it right - eliminate the simple functions (such as MoveTo, LineTo) which are entirely covered by more complex APIs (such as PolyLine). In .NET CF, you can't even create a pen wider than 1 pixel - because the overload that takes a pen width has been eliminated.

Other points of contention: no System.Diagnostics.Process class, so you can't create a process - you have to P/Invoke CreateProcess. You can't wait on more than one handle at a time with WaitHandle.WaitAny or WaitAll, because they've been removed (despite the underlying platform supporting WaitForMultipleObjects, at least for the WaitAny case). You can't poll a wait handle because the only overload of WaitOne left is the one that takes no parameters.

More seriously, it's not CLI compliant: the Thread class has no Abort or Join methods.

When trying to get back from a background thread to a UI thread, in order to update UI state (which you must, otherwise you may deadlock or have other synchronisation problems) you use Control.Invoke. .NET CF eliminates the overload which can take parameters: you're stuck with using the EventHandler delegate, which gives you the current object and an empty EventArgs. The desktop pattern looks something like:

private void ctl_HandleEvent( object sender, CustomEventArgs e )
if ( this.InvokeRequired )
new CustomEventHandler( ctl_HandleEvent ),
new object[] { sender, e }

// Do normal handling

You can't do this in .NET CF because you don't have InvokeRequired or the two-argument variant of Invoke. You have to cache whatever's in the CustomEventArgs somewhere, then Invoke a different method.

So the net result of omitting the metadata for these overloads (which cover the versions with fewer arguments) is that far more metadata is introduced into the program in order to try to achieve the goal.

And don't get me started on marshalling...

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