Can Windows Workflows be written in C# instead of XAML?

Question

We are using Windows Workflow Foundation for our workflows. The XAMLX files that contain workflow definitions are very brittle (they often end-up unopenable for no apparent reason) and we can't work on them in parallel, because we won't be able to merge those changes (underlying XAML is nie-human-readable). I'm looking for ways to alleviate the pains of having to work with XAML via built-in Visual Studio editor. Is it possible to define Windows Workflow Foundation workflows in C#?

This article article in the "Workflow Structure" section suggests that it is possible, but does not give full example.

Final Update Check the answer below for a working sample of code-only C# workflow and config to host it via WCF.

Answer 1

I have compiled together information from different tutorials and came up with a sample project demonstrating Windows Workflow Foundation workflow authored via code-only and hosted as WCF service

Answer 2

Absolutely - just compose your activities exactly as you would in Xaml. For example, the following will create a Sequence containing two WriteLine activities.

// Create a sequence containing 2 WriteLine activities.
var sequence = new Sequence();

sequence.Activities.Add(new WriteLine()
{
    Text = "Hello!"
});

sequence.Activities.Add(new WriteLine()
{
    Text = "Goodbye!"
});

// Now execute the sequence.
var wfApplication = new WorkflowApplication(sequence);
wfApplication.Run();

If you want to create custom activities, you need to inherit from CodeActivity or NativeActivity - but there's lots of examples of this on the web :)