Cannot write positional parameters in the current state. The writer cannot write the positional parameters in attribute form ...

Cannot write positional parameters in the current state.  The writer cannot write the positional parameters in attribute form because the writer has started to write elements, nor can the writer expand the positional parameters due to the lack of a default constructor on the markup extension that contains the positional parameters.  Try moving the positional parameter member earlier in the node stream, to a place where XamlXmlWriter can still write attributes.

Cannot write a CLR value that maps to number, array, object, true, false or null in JSON after a string value has been written. ... Cannot write a node of type XmlAttribute as an element value. Use XmlAnyAttributeAttribute with an array of XmlNode or XmlAttribute ... Cannot write positional parameters in the current state. The writer cannot write the positional parameters in attribute form ... Cannot write positional parameters in the current state. The writer cannot write the positional parameters in attribute form ... Cannot write positional parameters in the current state. The writer cannot write the positional parameters in attribute form ... Cannot write to a BufferedStream while the read buffer is not empty if the underlying stream is not seekable. Ensure that ... Case key '{0}' is not of type '{1}' and may not ever match any value yielded by the Switch Expression of type 'InArgument ... Casting to Decimal is not supported in LINQ to Entities queries, because the required precision and scale information cannot ... Category '{0}' is marked as multi-instance. Performance counters in this category can only be created with instance names. ...