Loading up to 32768 Pictureboxes in Visual Basic - vb.net

Question

I have a app which is loading between 32^2 to 32768 8x8 px pictureboxes. All pictureboxes are on screen so I need to load them all and can't just load some.
As it stands, my program won't even run. Is there a better way to load that many pictureboxes?
I would like to share with you my project, but I don't know how to.............
Thanks though!

Answer 1

You'd likely run into a MemoryOverflowException with this design. From the sound of it, you're probably trying to render a map of some sort if that's the case then this answer is for you (otherwise just ignore it).
At a high level you should only create the number of PictureBox controls that can fit on the screen at any given time. You can calculate this with the following function:
Private Function CalculateSizeToFitParent(ByVal parent As Control, ByVal childSize As Size) As Size
Return New Size(parent.Width \ childSize.Width, parent.Height \ childSize.Height)
End Sub
You would implement it as such to create a PictureBox to fill up the visible area of the current Form:
Dim pictureBoxSize As Size = New Size(8, 8)
Dim visibleArea(pictureBoxSize.Width - 1, pictureBoxSize.Height - 1) As PictureBox
Dim numberOfPictureBoxes As Size = CalculateSizeToFitParent(Me, pictureBoxSize)
For x As Integer = 0 To numberOfPictureBoxes.Width - 1
For y As Integer = 0 To numberOfPictureBoxes.Height - 1
visibleArea(x, y) = New PictureBox() With {
.Location = New Point(x * pictureBoxSize.Width, y * pictureBoxSize.Height)
.Size = pictureBoxSize
}
Me.Controls.Add(visibleArea(x, y))
Next
Next
The next part is two-fold:
You need to keep track of where the top-left corner of the current visible are is
You will need to reload the images in the respective visual area of the map.
This assumes that you have a 2D array that stores your images. And please note that you don't recreate the PictureBox controls but rather you just reload the image of the existing control:
Private _currentLocation As Point = New Point(0, 0) ' If you're starting somewhere else change it here
Public Property CurrentLocation As Point
Get
Return _currentLocation
End Get
Set(ByVal value As Point)
If (value <> _currentLocation) Then
_currentLocation = value
Me.OnCurrentLocationChanged()
End If
End Set
End Property
Protected Overridable Sub OnCurrentLocationChanged()
RaiseEvent CurrentLocationChanged(Me, EventArgs.Empty)
End Sub
Public Event CurrentLocationChanged(ByVal sender As Object, ByVal e As EventArgs)
Private Sub MyForm_CurrentLocationChanged(ByVal sender As Object, ByVal e As EventArgs) Handles Me.CurrentLocationChanged
If (visibleArea Is Nothing) Then
Throw New Exception("The visible area has not been generated yet.")
End If
If (_currentLocation Is Nothing) Then
Throw New Exception("The CurrentLocation cannot be null.")
End If
Dim widthUpperBounds As Integer = My2DArrayOfImageLocations.GetUpperBounds(0) - 1
Dim heightUpperBounds As Integer = My2DArrayOfImageLocations.GetUpperBounds(1) - 1
For x As Integer = 0 To visibleArea.GetUpperBounds(0) - 1
For y As Integer = 0 To visibleArea.GetUpperBounds(1) - 1
If (x + _currentLocation.Width > widthUpperBounds OrElse y + _currentLocation.Height) Then
'This "block" is outside the view area (display a blank tile?)
Else
visibleArea(x, y).Load(My2DArrayOfImageLocations(x + _currentLocation.Width, y + _currentLocation.Height))
End If
Next
Next
End Sub
Now whenever you reset the CurrentLocation property (however you'd do that, e.g. arrow keys, asdw, etc.) it will redraw the visible area of the map.
Update
Please note that I "free-typed" this example and you may need to tweak it a bit. After some more thought, you'll probably also need to call the Refresh method of the PictureBox when you load in the image (I didn't test).