title: Tkinter Button command getting executed before clicking the button
body: <p>I have created a frame, In that i have two browse button, i want browse two file that ending with ".txt" extension and printing it on screen.</p>
  
  <p>In my scenario, browse function getting called before pressing Button's on the frame. Am expecting it should called when i press Button. Complete code attached. Kindly someone correct me what i did wrong.</p>
  
  <pre><code>from Tkinter import *
  import tkFileDialog as filedialog
  
  global filename
  
  root = Tk()
  
  def browsefunc(entry):
      entry = filedialog.askopenfilename(filetypes=[("Text files","*.txt")])
      print entry
  
  
  browsebutton1 = Button(root, text="Browsefile1", command=browsefunc("TXT_file1"))
  browsebutton1.pack()
  
  browsebutton2 = Button(root, text="Browsefile2", command=browsefunc("TXT_file2"))
  browsebutton2.pack()
  
  
  root.mainloop()
  </code></pre>