Magnetic Card swiping issue!

HI,
I am working in with card swiping reader, I swipe the card and get the value in a textbox.. what I am trying to do is to get the value stored in the database the moment I swipe the card autumaticly  , so basicaly  i dont want to click a bottom or press enter to submit the value. right now this is my code and I use on text change to submit the value to the data but i still have to press enter , any idea's well be appreciated, and I read about lost_focus event but i am not getting a clear idea about how to use it.


public void TRACK2_TextChanged(object sender, EventArgs e)
    {
        xxx cn = new xxx ("My Sql Connection");
        // Parse out the win id
        string STR1= TRACK2.Text.Substring(1, 9);
        TRACK2.Text = STR1;
    ...