Visual Basic - event until on keypress

Question

First off, I am really sorry about the vague title. I am pretty knew to stack overflow and I have no idea how to phrase this question. What I want is on a key press (say the up arrow) I want to move a picture box across the windows form until it collides with a separate picture box. Here's my code so far.

Private Async Sub Form1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown
    Select Case e.KeyCode
        Case Keys.Left
            Me.pBox1.Left -= 20
        Case Keys.Up
            Me.pBox1.Top -= 20
        Case Keys.Right
            Me.pBox1.Left += 20

        Case Keys.Down
            Me.pBox1.Top += 20

    End Select

That's not all the code, just the important part. Basically, on a key press, the picture box moves across the form. But, I have to continually hold down the key to keep it moving. What I want is to press a key, and have the picture box to move across the screen until it hits another picture box.

P.S. I already have the collision code. (pBox1.Bounds.IntersectsWith(pBox2.Bounds)) Please keep in mind that I am pretty knew to visual basic and stack overflow.

Answer 1

you can create a subroutine which contains the moving of the picturebox as well as detection logic. call it from inside Form1_keyDown(). Key things to remember:

1. use loop to simulate the moving instruction of clicking.
2. use thread.sleep to create delay effect
3. while picturebox is moving, use 'inTheMiddleOfMoving' flag to make sure that pressing any arrow keys have no effect (exit the subroutine).

4. exit the loop either when hitting picturebox2, or wait a certain timespan (this is important)

   Select Case e.KeyCode
       Case Keys.Left
           MovePictureBox(pbox1, pbox2, 20, KeyMovingDirection.Left)
   ...
   
   Public Enum KeyMovingDirection
     Left
     Right
     Top
     Bottom
   End Enum
   
   
   Private inTheMiddleOfMoving As Boolean = False
   Public Sub MovePictureBox(pbox1 As PictureBox, pbox2 As PictureBox, stepA 
      As Integer, direction As KeyMovingDirection)
   
     If inTheMiddleOfMoving Then Exit Sub
   
     Dim collided As Boolean = False
     Dim t As New Stopwatch
     t.Start()
     Do
       Select Case direction
           Case KeyMovingDirection.Left
               pbox1.Left -= stepA
           Case KeyMovingDirection.Right
               pbox1.Left += stepA
           Case KeyMovingDirection.Top
               pbox1.Top -= stepA
           Case KeyMovingDirection.Bottom
               pbox1.Top += stepA
       End Select
       inTheMiddleOfMoving = True
   
       Threading.Thread.Sleep(200)
       If pbox1.Bounds.IntersectsWith(pbox2.Bounds) OrElse t.ElapsedMilliseconds > 5000 Then
           '...
           collided = True
       End If
     Loop Until collided
     t.Stop()
      inTheMiddleOfMoving = False
    End Sub