How to get the child component value in parent component

SampleEvent.evt

--------------------

<aura:event type="component"  description="This is my first Event">

<aura:attribute name="info"  type="String"/>

</aura:event>

ChildComponent.cmp

------------------

<aura:component>

<aura:registerEvent name="SampleComponentEvent" type="c:SampleEvent"/>

<ui:button label="Showdata"  press="{!c.childComponentMethod}"/>

</aura:component>

ChildComponentController

------------------------

({

childComponentMethod:function(component,event,helper){

var v1=component.getEvent("SampleComponentEvent");

v1.setParams({

"info":"Brahmanaidu"

 

});

v1.fire();

}

})

ParentComponent.cmp

--------------------------

<aura:component>

<aura:attribute name="eventmessage"   type="String"/>

<aura:handler name="SampleComponentEvent" event="c:SampleEvent" action="{!c.parentComponentMethod}"/>

<c:ChildComponent/>

    Value is {!v.eventmessage}

</aura:component>

ParentComponent controller

----------------------------------

({

parentComponentMethod:function(component,event,helper){

var getvalue=event.getParam("info");

component.set("v.eventmessage",getvalue+'sfdcscenarios.blogspot.com');

}

})

Lightning application

--------------------------

<aura:application extends="force:slds">

<c:ParentComponent/>

</aura:application>