OLE: Inaccessible due to its protection level. - vb.net

Question

I am trying to plot a chart in excel sheet using VB.
So now I am following the instructions given here
1- I started a new VB project in VS2010, called Excelgraph.
2- By default I got Form1.vb[Design].
3- On this Form I created a button by dragging it from the toolbox.
4-I doubled clicked it and new Form1.vb opens.
5- I removed everything that was automatically generated in this file i,e Form1.vb file and pasted the following code:
Updated Code
This is another code and is a latest one, compatible with Visual Basic 6.0.
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button1.Click
Dim oXL As Object ' Excel application
Dim oBook As Object ' Excel workbook
Dim oSheet As Object ' Excel Worksheet
Dim oChart As Object ' Excel Chart
Dim iRow As Integer ' Index variable for the current Row
Dim iCol As Integer ' Index variable for the current Row
Const cNumCols = 10 ' Number of points in each Series
Const cNumRows = 2 ' Number of Series
ReDim aTemp(0 To cNumRows, 0 To cNumCols)
'Start Excel and create a new workbook
oXL = CreateObject("Excel.application")
oBook = oXL.Workbooks.Add
oSheet = oBook.Worksheets.Item(1)
' Insert Random data into Cells for the two Series:
Randomize(Now().ToOADate())
For iRow = 1 To cNumRows
For iCol = 1 To cNumCols
aTemp(iRow, iCol) = Int(Rnd() * 50) + 1
Next iCol
Next iRow
oSheet.Range("A1").Resize(cNumRows, cNumCols).Value = aTemp
'Add a chart object to the first worksheet
oChart = oSheet.ChartObjects.Add(50, 40, 300, 200).Chart
oChart.SetSourceData(Source:=oSheet.Range("A1").Resize(cNumRows, cNumCols))
' Make Excel Visible:
oXL.Visible = True
oXL.UserControl = True
End Sub
End Class
Update
I updated the code as shown above.
Error
'aTemp' is not declared. It may be inaccessible due to its protection level.
c:\users\ybf4 \documents\visual studio 2010\Projects\Excelgraph2
\Excelgraph2\Form1.vb
There were two more errors which I managed to remove. How do I remove this error?
I am compiling the above code on visual studio 2010 and Office is Office 2007.

Answer 1

A simple, trivial program reveals the error to be as I suspected - you can't change the size of something that doesn't exist!
As Derek said, you need to change the ReDim to Dim - OR you need to declare it first.
FAILS:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Const cNumCols = 10 ' Number of points in each Series
Const cNumRows = 2 ' Number of Series
ReDim aTemp(0 To cNumRows, 0 To cNumCols)
End Sub
PASSES:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Const cNumCols = 10 ' Number of points in each Series
Const cNumRows = 2 ' Number of Series
Dim aTemp
ReDim aTemp(0 To cNumRows, 0 To cNumCols)
End Sub
PASSES:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Const cNumCols = 10 ' Number of points in each Series
Const cNumRows = 2 ' Number of Series
Dim aTemp(0 To cNumRows, 0 To cNumCols)
End Sub
Hovering over aTemp should have told you this - it should also be underlined by a blue squiggly line to indicate a problem.

Answer 2

It's been a long time since I did this, but just looking at the code I suspect you need to change:
ReDim aTemp(0 To cNumRows, 0 To cNumCols)
To:
Dim aTemp(0 To cNumRows, 0 To cNumCols)
ReDim is used to re-dimension an array after it has been dimensioned (using the Dim statement)

Answer 3

That's remarkably old code (it's for VB3, so 4 generations before the first VB.Net, and Excel 5)
However, I believe your code should run fine if you just comment out the two lines indicated.
The randomness of the entries added to the worksheet may be different, but since you'll be replacing that code anyway (where Rnd() is used), it shouldn't matter. (I'm assuming your purpose isn't to generate random graphs)
As to DoEvents, I'm not sure that was ever necessary.