Get selected object in rhino document (c#)

Hi. I amd trying to create a c# component that will let user to select object in rhino to import object to grasshopper.

here is the process I would like to create :

Using button(this is important. not toggle.),

if activated,

to rhino command line, "select object to reference" then wait for user to select an object and hit enter.

then the component will reference that object from then on.

//end

I do not want to use timer since following definition is very heavy.

can anyone help me with this?