PictureBox1_Paint and declaring variables [RESOLVED]

[stephen weber]

Hi,

I would just like to create a list of points through some algorithm under Private Sub Form1_Load
and then have them displayed with drawellipse(pens.black,x(a),y(a),1,1) under
Private Sub PictureBox1_Paint.

I have the variables x(), y() and 'a' as public singles ontop in the class arena.
And declare them again in Private Sub Form1_Load when I calculate how many points needed x(a),y(a)....

But in the error analysis when the program runs, apparently the variables aren't public enough because they are listing as unfilled.

Am I declaring the variables correctly or is it that
Private Sub PictureBox1_Paint
tries to paint before the number of points are calculated?

Thanks for you's help..

[jmcilhinney]

You say that you are declaring your variables at the class level and the method level. This means that the local variables in the method are shadowing the class-level variables, i.e. they are not the same variables. In your method, try tesing the values of the variable a and the variable Me.a to see whether this is the case. Sorry if I have misinterpreted the situation but that is what it sounds like. We might need to see some code otherwise.

[stephen weber]

Ok.. (You got me). That is clearer.. Me.a() as a global..
How about this. I can declare a() at the class level, but at that level I don't yet know the size of the dimension until a calculation in method. I thought I could then initiate my global a() as a(g) where g is my calculated size. I understand you are telling me that I am just creating a local variable a(g) not defining my global a().

So how do I send a list of points to a paint method?

[jmcilhinney]

You can declare an array variable at the class-level and then set it's length like this:

Private a() As Integer
 
    Private Sub ResetArray()
        ReDim Me.a(10)
    End Sub

or, given that you haven't actually set a length in the declaration, simply assign a new array to it:

Private a() As Integer
 
    Private Sub ResetArray()
        Me.a = New Integer() {1, 2, 3, 4}
    End Sub

Edit:
Note that, unless you need to access the array from more than one method, it doesn't need to be class-level and you can just declare a local variable when and where you need it.

[stephen weber]

Thank you,

I know it took me awhile to reply. I got busy and also read a few books on this. The program works now.