Problems with Buttons in Visual Basic

Question

I'm trying to write a Tic Tac Toe program in Visual Basic that is played between the user and the computer. The program uses a 2D array in a module to keep track of the state of the game. Here's the code I have so far.

Public Class Form1

Private _currentPlayer As String = "O"
Private _gameArray As String

Private Property gameArray(p1 As Integer, p2 As Integer) As String
    Get
        Return _gameArray
    End Get
    Set(value As String)
        _gameArray = value
    End Set
End Property

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    MessageBox.Show("Welcome to Tic Tac Toe! Would you like to play a game?")
End Sub

Private Function nextPlayer() As String

    If _currentPlayer.Equals("O") Then
        _currentPlayer = "X"
        Return "O"
    Else
        _currentPlayer = "O"
        Return "X"
    End If

End Function

Private Sub printView()
    Console.WriteLine(btn1.Text & "|" & btn2.Text & "|" & btn3.Text)
    Console.WriteLine("----------------")
    Console.WriteLine(btn4.Text & "|" & btn5.Text & "|" & btn6.Text)
    Console.WriteLine("----------------")
    Console.WriteLine(btn7.Text & "|" & btn8.Text & "|" & btn9.Text)
End Sub

Private Sub Form1_KeyPress(sender As Object, e As KeyPressEventArgs) Handles MyBase.KeyPress
    Console.WriteLine(e.KeyChar)

    Select Case e.KeyChar
        Case "1"
            btn1.Text = "X"
        Case "2"
            btn2.Text = "X"
        Case "3"
            btn3.Text = "X"
        Case "4"
            btn4.Text = "X"
        Case "5"
            btn5.Text = "X"
        Case "6"
            btn6.Text = "X"
        Case "7"
            btn7.Text = "X"
        Case "8"
            btn8.Text = "X"
        Case "9"
            btn9.Text = "X"
    End Select
    printView()
End Sub

Private Sub btn1_Click(sender As Object, e As EventArgs) Handles btn1.Click
    If Not String.IsNullOrEmpty(btn1.Text) Then
        MessageBox.Show("This position has already been taken, please select an empty square.")
    Else
        btn1.Text = nextPlayer()
        gameArray(0, 0) = nextPlayer()
        checkwin()
    End If
End Sub

Private Sub btn2_Click(sender As Object, e As EventArgs) Handles btn2.Click
    If Not String.IsNullOrEmpty(btn2.Text) Then
        MessageBox.Show("This position has already been taken, please select an empty square.")
    Else
        btn2.Text = nextPlayer()
        gameArray(0, 1) = nextPlayer()
        checkwin()
    End If

End Sub

Private Sub btn3_Click(sender As Object, e As EventArgs) Handles btn3.Click
    If Not String.IsNullOrEmpty(btn3.Text) Then
        MessageBox.Show("This position has already been taken, please select an empty square.")
    Else
        btn3.Text = nextPlayer()
        gameArray(0, 2) = nextPlayer()
        checkwin()
    End If

End Sub

Private Sub btn4_Click(sender As Object, e As EventArgs) Handles btn4.Click
    If Not String.IsNullOrEmpty(btn4.Text) Then
        MessageBox.Show("This position has already been taken, please select an empty square.")
    Else
        btn4.Text = nextPlayer()
        gameArray(1, 0) = nextPlayer()
        checkwin()
    End If
End Sub

Private Sub btn5_Click(sender As Object, e As EventArgs) Handles btn5.Click
    If Not String.IsNullOrEmpty(btn5.Text) Then
        MessageBox.Show("This position has already been taken, please select an empty square.")
    Else
        btn5.Text = nextPlayer()
        gameArray(1, 1) = nextPlayer()
        checkwin()
    End If
End Sub

Private Sub btn6_Click(sender As Object, e As EventArgs) Handles btn6.Click
    If Not String.IsNullOrEmpty(btn6.Text) Then
        MessageBox.Show("This position has already been taken, please select an empty square.")
    Else
        btn6.Text = nextPlayer()
        gameArray(1, 2) = nextPlayer()
        checkwin()
    End If
End Sub

Private Sub btn7_Click(sender As Object, e As EventArgs) Handles btn7.Click
    If Not String.IsNullOrEmpty(btn7.Text) Then
        MessageBox.Show("This position has already been taken, please select an empty square.")
    Else
        btn7.Text = nextPlayer()
        gameArray(2, 0) = nextPlayer()
        checkwin()
    End If
End Sub

Private Sub btn8_Click(sender As Object, e As EventArgs) Handles btn8.Click
    If Not String.IsNullOrEmpty(btn8.Text) Then
        MessageBox.Show("This position has already been taken, please select an empty square.")
    Else
        btn8.Text = nextPlayer()
        gameArray(2, 1) = nextPlayer()
        checkwin()
    End If
End Sub

Private Sub btn9_Click(sender As Object, e As EventArgs) Handles btn9.Click
    If Not String.IsNullOrEmpty(btn9.Text) Then
        MessageBox.Show("This position has already been taken, please select an empty square.")
    Else
        btn9.Text = nextPlayer()
        gameArray(2, 2) = nextPlayer()
        checkwin()
    End If
End Sub

Private Sub checkwin()

    If (btn1.Text = "X") And (btn2.Text = "X") And (btn3.Text = "X") Then MsgBox("X WINS!")
    If (btn4.Text = "X") And (btn5.Text = "X") And (btn6.Text = "X") Then MsgBox("X WINS!")
    If (btn7.Text = "X") And (btn8.Text = "X") And (btn9.Text = "X") Then MsgBox("X WINS!")
    If (btn1.Text = "X") And (btn4.Text = "X") And (btn7.Text = "X") Then MsgBox("X WINS!")
    If (btn2.Text = "X") And (btn5.Text = "X") And (btn8.Text = "X") Then MsgBox("X WINS!")
    If (btn3.Text = "X") And (btn6.Text = "X") And (btn9.Text = "X") Then MsgBox("X WINS!")
    If (btn1.Text = "X") And (btn5.Text = "X") And (btn9.Text = "X") Then MsgBox("X WINS!")
    If (btn3.Text = "X") And (btn5.Text = "X") And (btn7.Text = "X") Then MsgBox("X WINS!")

    If (btn1.Text = "O") And (btn2.Text = "O") And (btn3.Text = "O") Then MsgBox("O WINS!")
    If (btn4.Text = "O") And (btn5.Text = "O") And (btn6.Text = "O") Then MsgBox("O WINS!")
    If (btn7.Text = "O") And (btn8.Text = "O") And (btn9.Text = "O") Then MsgBox("O WINS!")
    If (btn1.Text = "O") And (btn4.Text = "O") And (btn7.Text = "O") Then MsgBox("O WINS!")
    If (btn2.Text = "O") And (btn5.Text = "O") And (btn8.Text = "O") Then MsgBox("O WINS!")
    If (btn3.Text = "O") And (btn6.Text = "O") And (btn9.Text = "O") Then MsgBox("O WINS!")
    If (btn1.Text = "O") And (btn5.Text = "O") And (btn9.Text = "O") Then MsgBox("O WINS!")
    If (btn3.Text = "O") And (btn5.Text = "O") And (btn7.Text = "O") Then MsgBox("O WINS!")
End Sub

End Class

As the code is written, the program isn't actually taking turns, just simply putting an O in whatever button I press.

I'm also supposed to make it possible for the user to both click the square they want, or use the keys 1-9 on the keyboard to select the box they want. I'm having trouble assigning the keys to their corresponding buttons.

Any help would be greatly appreciated.

Answer 1

Also try changing your code this way around so that you are not using the NOT clause....

Private Sub btn2_Click(sender As Object, e As EventArgs) Handles btn2.Click

    If String.IsNullOrEmpty(btn2.Text) Then
        MessageBox.Show("This position has already been taken, please select an empty square.")
    Else
        btn2.Text = nextPlayer()
        gameArray(0, 1) = nextPlayer()
    End If

End Sub

Answer 2

Again look at your code.... lets assume that _currentPlayer = O

Private Sub btn2_Click(sender As Object, e As EventArgs) Handles btn2.Click
If Not String.IsNullOrEmpty(btn2.Text) Then
    MessageBox.Show("This position has already been taken, please select an empty square.")
Else
    btn2.Text = nextPlayer()    ' this will return O and _currentPlayer is now X
    gameArray(0, 1) = nextPlayer() 'Your calling it again so return will be X and _currentPlayer in now O again... 
    checkwin()
End If

As this is a class projects... see if you can fix this yourself first.