While loop Control Problem / button problem

[VeliBayar]

According to my program, when user hits the toggle button the program starts to read from serial port. how it does this, button is wired to case structure and inside the case structure I defined while loop to maintain reading operation.. but the problem is when I hit the read toggle button to stop the program, it does not work since it cannot stop the while loop, still I have no solution, I will add the VI that I try some solutions on it.. 

[.aCe.]

Your read button is outside the while loop and hence it will only be read once. If you need it to be read every iteration of the while loop, you need to place the read control inside the while loop.