Help With Nested Loop

[Art W.]

I am trying to run a nested loop; it should call a result from a MDB database. Which it does, when I run the single loop it goes thru all of the entries. But when I try to get a number to display twice it stops on the second entry. Having it display the number twice is just a test to make sure it does work, I am going to modify it after I can prove the loop works. The count on the Message Box is correct, but the number displayed is wrong?

I want it to display each number twice and then move on to the next number.


Please see the code below.

Do Until number1 = 100
            If number1 <= 0 Then Exit Do
            number1 -= 1
            counter1 += 1
 
            If intCurrentIndex < ds.Tables(0).Rows.Count - 1 Then
                intCurrentIndex = intCurrentIndex + 1
 
                Do Until number2 = 10
                    If number2 <= 0 Then Exit Do
                    number2 -= 1
                    counter2 += 1
 
                    txtResults.Text = ds.Tables(0).Rows(intCurrentIndex).Item("Results").ToString()
                Loop
 
            End If
 
        Loop
 
        MsgBox("The loop ran " & counter1 * counter2 & " times.")

Any Ideas

Thanks

Art W.

[cicatrix]

I suppose number1 > 100 at the beginning, right?

because it will never become 100 within your cycle and your initial condition (until number1 = 100) won't happen. If it's zero in the beginning then this line will have your parent loop cycle only once:

If number1 <= 0 Then Exit Do

There's no need to use counter2 you can increment counter1 in the nested loop with the same result.

For the nested loop I suggest you use For ... Next construction (or For Each if you need to iterate through all of the rows):

For intCurrentIndex = whateverthestartingvalueis To ds.Tables(0).Rows.Count - 1
    counter1 +=1
    txtResults.Text = ds.Tables(0).Rows(intCurrentIndex).Item("Results").ToString()
Next

Mind the fact that txtResults.Text will contain only the last item because you assign a new text with each loop. If you need to see all results you should add text to it, not change it.

txtResults.AppendText(ds.Tables(0).Rows(intCurrentIndex).Item("Results").ToString() & Environment.NewLine())

[jmcilhinney]

Using Do loops to count is a poor choice. That's what For loops are for. If you want to traverse a DataTable then you should use For and/or For Each loops:

For Each row As DataRow In myDataTable.Rows
    For Each column As DataColumn In myDataTable.Columns
        MessageBox.Show(row(column).ToString())
    Next
Next

For rowIndex As Integer = 0 To myDataTable.Rows.Count - 1
    Dim row As DataRow = myDataTable.Rows(rowIndex)
 
    For columnIndex As Integer In myDataTable.Columns.Count - 1
        MessageBox.Show(row(columnIndex).ToString())
    Next
Next