Providing a default value for InArgument<T>
===

Old `System.ComponentModel` provides a `DefaultValueAttribute` that, when applied to a property, marks it as having a default value in tools such as the Windows Forms Designer.

Is there an equivalent attribute in the WPF/Workflow Foundation world? The following didn't work as expected:

    [DefaultValue('|')] // From System.ComponentModel
    public InArgument<char> ColumnSeparator { get; set; }

The WPF Designer ignores this attribute declaration.