C# 4 and .NET 4

Workflows ❘ 1335
}
vm.InitializeViewModel(new Sequence());
this.DataContext = vm;
Here, we construct the view model, and, by default, add in a Sequence activity so that something is
displayed onscreen when the application runs. Figure 44-15 shows what the screen looks like if you run the
application at this point.
figure 44-15
The only part missing now is some commands. We use a DelegateCommand class to write ICommand-based
commands for WPF, as then we find the code in the view model is easy to understand. The commands are
fairly trivial to implement, as is evident by the New command shown here:
public ICommand New
{
get
{
return new DelegateCommand(unused =>
{
InitializeViewModel(new Sequence());
});
}
}
This command is bound to the New menu item, so when that is clicked the delegate is executed, and in
this instance that simply calls the InitializeViewModel method with a new Sequence activity. Because
this method also raises the property change notification for the designer and the property grid, these are
updated, too.
The Open command is a little more involved but not much:
public ICommand Open
{
get
{
return new DelegateCommand(unused =>
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