Creating custom command

Hi ,

I have tried to create a custom command to ribbon to get children count.

followed steps,

1.Created a class to get children.

2.in commands.config file i have included type.

<commands>
<command name="item:getchildcount" type="GlassMapper.Helpers.GetChildrenCount,GlassMapper.Helpers"/>

3.in core db i've created a item for apperaing and getting results.

 

4.all now set, but when i click the count children from ribbon, nothing happens, what i missed?

Any help?