I need some Help (Sudoku Gen)

[Tom.]

Hey everyone,

I'm creating a Sudoku code with Visual Basics 2005 Express. However, an error appears saying the code is on a infinite loop

 Private Sub Sudoku_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged, TextBox2.TextChanged, TextBox3.TextChanged, TextBox4.TextChanged, TextBox5.TextChanged, TextBox6.TextChanged, TextBox7.TextChanged, TextBox8.TextChanged, TextBox9.TextChanged, TextBox10.TextChanged, TextBox11.TextChanged, TextBox12.TextChanged, TextBox13.TextChanged, TextBox14.TextChanged, TextBox15.TextChanged, TextBox16.TextChanged, TextBox17.TextChanged, TextBox18.TextChanged, TextBox19.TextChanged, TextBox20.TextChanged, TextBox21.TextChanged, TextBox22.TextChanged, TextBox23.TextChanged, TextBox24.TextChanged, TextBox25.TextChanged, TextBox26.TextChanged, TextBox27.TextChanged, TextBox28.TextChanged, TextBox28.TextChanged, TextBox29.TextChanged, TextBox30.TextChanged, TextBox31.TextChanged, TextBox32.TextChanged, TextBox33.TextChanged, TextBox34.TextChanged, TextBox35.TextChanged, TextBox36.TextChanged, TextBox37.TextChanged, TextBox38.TextChanged, TextBox39.TextChanged, TextBox40.TextChanged, TextBox41.TextChanged, TextBox42.TextChanged, TextBox43.TextChanged, TextBox44.TextChanged, TextBox45.TextChanged, TextBox46.TextChanged, TextBox47.TextChanged, TextBox48.TextChanged, TextBox49.TextChanged, TextBox50.TextChanged, TextBox51.TextChanged, TextBox52.TextChanged, TextBox53.TextChanged, TextBox54.TextChanged, TextBox55.TextChanged, TextBox56.TextChanged, TextBox57.TextChanged, TextBox58.TextChanged, TextBox59.TextChanged, TextBox60.TextChanged, TextBox61.TextChanged, TextBox62.TextChanged, TextBox63.TextChanged, TextBox64.TextChanged, TextBox65.TextChanged, TextBox66.TextChanged, TextBox67.TextChanged, TextBox68.TextChanged, TextBox69.TextChanged, TextBox70.TextChanged, TextBox71.TextChanged, TextBox72.TextChanged, TextBox73.TextChanged, TextBox74.TextChanged, TextBox75.TextChanged, TextBox76.TextChanged, TextBox77.TextChanged, TextBox78.TextChanged, TextBox79.TextChanged, TextBox80.TextChanged, TextBox81.TextChanged
        Dim a As Integer
        Dim solfound As Boolean = True
        Dim textbox As TextBox = CType(sender, TextBox)

        If Not SolutionShwn Then
            If textbox.Text = "" Then
                textbox.Text = "1"
            ElseIf textbox.Text = "9" Then
                textbox.Text = ""
            Else
                textbox.Text = Trim(Str(CInt(textbox.Text) + 1))
            End If
            For a = 1 To 81
                If txtbox(a).Text <> Sudokusolution(a) Then
                    solfound = True
                    Exit For
                End If
            Next a
            congrats.Visible = solfound
        End If
    End Sub

The

textbox.Text = Trim(Str(CInt(textbox.Text) + 1))

Line reports an infinite loop, but I can't seem to fix the problem, any help would be greatly appreciated, thanks.

[Fromethius]

What do you mean? Like.. That is the only code that is running?.. Or.. cmon guys be more specific ccmmonnnnnnnnnnn

[Shaggy Hiker]

Well, there's junk in there you don't need, so why not get it out. Try something like this:

textbox.Text = (CInt(textbox.Text) + 1).ToString

After all, Str() isn't such a good idea. ToString is better, in this case, and Trim() would only remove spaces that wouldn't exist anyways, because ToString on an integer won't give you any spaces.

However, that's not such a good idea, either, because if the contents of the textbox is not actually an integer, CInt() will throw an exception. You show signs of having come from VB6 (the use of Str()), so you may be expecting CInt() to be as exception free as Val(), but it isn't. Passing in "123a" would return 123 if you used Val, but will throw an exception under CInt().

A better solution would be to use Integer.TryParse(), but you pass in the variable that you want the integer to be returned in as the second argument:

dim i as integer
 
If Integer.TryParse(Textbox.Text,i) then
 'TryParse will return true if it works. i has the integer.
 Textbox.Text = i.ToString
else
 'This means that the textbox doesn't hold an integer.
end if

This requires more code, but it is safer because you won't get an exception.

[Bulldog]

I think the reason you get an infinite loop is because you alter a textbox text in the sub, which in turn initiates a new textbox changed event, which causes another textbox changed event then another and another etc.

The solution would be to inhibit the event while you update the textbox content (or to use a completely different method!).

[Shaggy Hiker]

Oh yeah, that's the reason for the loop. All that other stuff I was talking about was just improvements on the code.

[Bulldog]

As a quick and dirty test (just to check this is the problem) try;

    Dim Inhibit As Boolean = False

    Private Sub Sudoku_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged, TextBox2.TextChanged, TextBox3.TextChanged, TextBox4.TextChanged, TextBox5.TextChanged, TextBox6.TextChanged, TextBox7.TextChanged, TextBox8.TextChanged, TextBox9.TextChanged, TextBox10.TextChanged, TextBox11.TextChanged, TextBox12.TextChanged, TextBox13.TextChanged, TextBox14.TextChanged, TextBox15.TextChanged, TextBox16.TextChanged, TextBox17.TextChanged, TextBox18.TextChanged, TextBox19.TextChanged, TextBox20.TextChanged, TextBox21.TextChanged, TextBox22.TextChanged, TextBox23.TextChanged, TextBox24.TextChanged, TextBox25.TextChanged, TextBox26.TextChanged, TextBox27.TextChanged, TextBox28.TextChanged, TextBox28.TextChanged, TextBox29.TextChanged, TextBox30.TextChanged, TextBox31.TextChanged, TextBox32.TextChanged, TextBox33.TextChanged, TextBox34.TextChanged, TextBox35.TextChanged, TextBox36.TextChanged, TextBox37.TextChanged, TextBox38.TextChanged, TextBox39.TextChanged, TextBox40.TextChanged, TextBox41.TextChanged, TextBox42.TextChanged, TextBox43.TextChanged, TextBox44.TextChanged, TextBox45.TextChanged, TextBox46.TextChanged, TextBox47.TextChanged, TextBox48.TextChanged, TextBox49.TextChanged, TextBox50.TextChanged, TextBox51.TextChanged, TextBox52.TextChanged, TextBox53.TextChanged, TextBox54.TextChanged, TextBox55.TextChanged, TextBox56.TextChanged, TextBox57.TextChanged, TextBox58.TextChanged, TextBox59.TextChanged, TextBox60.TextChanged, TextBox61.TextChanged, TextBox62.TextChanged, TextBox63.TextChanged, TextBox64.TextChanged, TextBox65.TextChanged, TextBox66.TextChanged, TextBox67.TextChanged, TextBox68.TextChanged, TextBox69.TextChanged, TextBox70.TextChanged, TextBox71.TextChanged, TextBox72.TextChanged, TextBox73.TextChanged, TextBox74.TextChanged, TextBox75.TextChanged, TextBox76.TextChanged, TextBox77.TextChanged, TextBox78.TextChanged, TextBox79.TextChanged, TextBox80.TextChanged, TextBox81.TextChanged
        If Not Inhibit Then
            
            Inhibit = True

            Dim a As Integer
            Dim solfound As Boolean = True
            Dim textbox As TextBox = CType(sender, TextBox)

            If Not SolutionShwn Then
                If textbox.Text = "" Then
                    textbox.Text = "1"
                ElseIf textbox.Text = "9" Then
                    textbox.Text = ""
                Else
                    textbox.Text = Trim(Str(CInt(textbox.Text) + 1))
                End If
                For a = 1 To 81
                    If txtbox(a).Text <> Sudokusolution(a) Then
                        solfound = True
                        Exit For
                    End If
                Next a
                congrats.Visible = solfound
             End If

             Inhibit = False
        End If
    End Sub