How can i get the text of entry in TK?

hi everyone!
I want to get the text of entry in TK,when run the script,I input
the value "test" in the entry,but click the button "get",It just show
the value "Null",not the value "test" which is except.
  what is the wrong? the script is as below:

require 'tk'

root=TkRoot.new{
title "getValue"
}

var=TkVariable.new
a=TkEntry.new(root){
   text=var
  grid 'row'=>1,'column'=>1
}

TkButton.new(root){
  text "get"
  grid 'row'=>3,'column'=>1
  command{
     puts a.cget('text')

  }
}

Tk.mainloop

slaughter wrote:

hi everyone!
I want to get the text of entry in TK,when run the script,I input
the value "test" in the entry,but click the button "get",It just show
the value "Null",not the value "test" which is except.
  what is the wrong? the script is as below:

require 'tk'

root=TkRoot.new{
title "getValue"
}

var=TkVariable.new
a=TkEntry.new(root){
   text=var
  grid 'row'=>1,'column'=>1
}

TkButton.new(root){
  text "get"
  grid 'row'=>3,'column'=>1
  command{
     puts a.cget('text')

  }
}

Tk.mainloop

Here is a working example.

You used the method cget, I believe the correct method is value.