mx.processor.xasAction is deprecated a long time ago. It is better to use mx.ui.action to execute a microflow. By adding a breakpoint in the microflow and inspecting the variables, you would notice that the object is not passed to the microflow. That is because the applyto property is not defined. This would fix it for you:
mx.ui.action(this.callbackMF, {
params: {
guids: [this.dataobject.getGuid()],
applyto: "selection"
},
callback: function(output) {
console.log(out);
}
}, this);
By passing 'this' as the third parameter, the error and callback handler are executed in this scope, so there is no need to use dojo.hitch. Note that MxObject.getGUID is also deprecated. (When using index-console.html, the deprecation messaged are printed to your console).