wpf - Exception: 'IValueConverter' type does not have a public TypeConverter class -

I have just run this exception in the IvalueConverter:

type of IValueConverter Do not have a public typewriter class

Has anyone else come on this? What is the reason, and how can I fix it? Thank you. Simple solution, as it turns out, I had referred to my value converter like this:

  & lt; Binding path = "foreground" converter = "static resource brush to rbb converter" converter parameter = "b" />  

In return:

  & lt; Binding path = "foreground" converter = "{static resource brushesorbub converter}" converter parameter = "b" />  

In other words, I left the braces from my converter context.