Same old "object reference not set to an instance of an object" problem...

[Fire00f1y]

So, I've been cruising these and many other forums and have found many who need help concerning this issue, but usually it's resolved using the New statement.

What I'm doing here is I first add a 2D array of PictureBoxes during runtime with the following code

For i = 0 To xVal
            For z = 0 To yVal
                pictures(i, z) = New PictureBox
                currentPoint = New Point(startX + (z * 30), startY + (i * 30))
                pictures(i, z).Location = currentPoint
                pictures(i, z).Size = picSize
                pictures(i, z).BackColor = Color.Black
                pictures(i, z).BorderStyle = BorderStyle.FixedSingle
                pictures(i, z).Name = counter
                counter += 1
            Next
        Next

        For i = 0 To xVal
            For z = 0 To yVal
                Me.Controls.Add(pictures(i, z))
                AddHandler pictures(i, z).Click, AddressOf pictureClick
            Next
        Next

Then later, I have a separate Sub which is supposed to change every picturebox in the array to the same image with this code:

Private Sub All()

        For i = 0 To x
            For j = 0 To y
                pictures(i, j).Image = New Bitmap("images/" & filePic & ".jpg")
            Next
        Next
    End Sub

I know that the first code works because if I coment out Private Sub All() then it works fine, but the line

pictures(i, j).Image = New Bitmap("images/" & filePic & ".jpg")

returns the Object reference not set to an instance of an object error. An alternative code I had was:

Private Sub All()
        Dim index As Integer

        For i = 0 To x
            For j = 0 To y
                grid(index) = filePic
                pictures(i, j).Image = New Bitmap("images/" & filePic & ".jpg")
                index += 1
            Next
        Next
    End Sub

where "grid()" was a string array holding lines of integers for map placement

Any help on this topic would be greatly appreciated... it's been stumping me for a day or so now

Edit: I had this problem in a separate location in my code and while playing around with different solutions I somehow solved it for that instance of the error, but not this one. No idea how :'(

[Teme64]

Most likely you have "off-by-one" error while indexing the matrix. Try this in sub All()

For i = 0 To x
  For j = 0 To y
    If i > pictures.GetUpperBound(0) OrElse j > pictures.GetUpperBound(1) Then
      ' Debug
      MessageBox.Show("Out of bounds", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
    End If
    If pictures(i, j) Is Nothing Then
      ' Debug
      MessageBox.Show("Missing picture box, i=" & i.ToString & ", j=" & j.ToString, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
    End If
    pictures(i, j).Image = New Bitmap("images\" & FilePic & ".jpg")
  Next
Next

This should trap (i.e. show a message box) if your code tries to access a non-existing picture box or goes out of bounds.

I changed also pictures(i, j).Image = New Bitmap("images/" & FilePic & ".jpg") to pictures(i, j).Image = New Bitmap("images\" & FilePic & ".jpg") . Windows uses backward slashes, not forward slashes in file paths.

[Fire00f1y]

First of all, thanks for the response!

But that didn't work. I know the index is correct, I've used that same method elsewhere in the code.

With that being said, I did try your block to debug and see if it would give me insight into my problem... but it just spit out the same error, this time on the line:

If i > pictures.GetUpperBound(0) OrElse j > pictures.GetUpperBound(1) Then

I really think my problem is in the picturebox array, maybe in the manner in which I declared and specified it.

I actually declare the array as a global variable and then assign it parameters and values in the code block I posted above to avoid having to pass the array from one sub to another if I needed to use it for something.

Thanks for the interest :D

EDIT: Also, before posting, I ran the program and had it pause on the line before it gave me problems so I could see the values being sent to it and they were all within the correct range and in the proper place.

[Teme64]

I actually declare the array as a global variable

Nothing wrong with that.

I really think my problem is in the picturebox array, maybe in the manner in which I declared and specified it.

Yes it can be that. Or your code may set the array (matrix actually) to nothing somewhere? Or you have a scope issue i.e. you declare a variable called pictures twice?

Did you check all these values: If i > pictures.GetUpperBound(0) OrElse j > pictures.GetUpperBound(1) Then ?
If you get an error in that line, stop the execution right before the line, open the immediate window (Ctrl-G) and type following (press Enter after each print statement):
? i
? pictures.GetUpperBound(0)
? j
? pictures.GetUpperBound(1)
you can check that values are correct or you do get "object reference..." error from either ? pictures.GetUpperBound(0) or ? pictures.GetUpperBound(1) .

How do you declare pictures array (matrix). With something like

Public pictures(2, 2) As PictureBox ' Global 3x3 matrix

perhaps, or

Public pictures(, ) As PictureBox
.
.
ReDim pictures(2, 2) ' Global 3x3 matrix

Without seeing the whole code, I have to throw all possible causes for that error :)

[Vandamn]

I think Teme64 is right!

how have you declared your variable "pictures" and where?

maybe from there it will give us further insight into how the variable has been dimensioned.