Recently made a supermarket front desk cashier procedure, in the main interface of a text box and commodity bar code, but sometimes the window loses focus, this time to sweep out the bar code, click the mouse to activate the form must be in the form to sweep code again, now need to let the application at run time will never loses focus, how to do? Windows desktop can also, shield the operation of other programs can also, in short they can realize their own program never loses focus, which a great god knows the way of thinking?