我的程式碼:

Public Class Form1
    Dim pictureBox As PictureBox() = New PictureBox(80) {}
    Dim attachObstaclesMinimum As Integer = 20
    Dim attachObstaclesMaximum As Integer = 50
    Private Sub setPictureBox(sender As Object, e As EventArgs) Handles Me.Load
        For y = 0 To 8
            For x = 0 To 8
                Dim i As Integer = y * 9 + x
                Me.Controls.Add(pictureBox(i))
                pictureBox(i) = New PictureBox
                pictureBox(i).Name = "pictureBox" & i
                pictureBox(i).Text = i
                pictureBox(i).Size = New Size(50, 50)
                pictureBox(i).Location = New Point(50 * (x) + 12, 50 * (y) + 12)
            Next
        Next
    End Sub

    Private Sub ButtonSet_Click(sender As Object, e As EventArgs) Handles ButtonSet.Click
        For y = 0 To 8
            For x = 0 To 8
                Dim i As Integer = y * 9 + x
                pictureBox(i).BackColor = Color.White
            Next
        Next
    End Sub

    Private Sub AttachObstacles_Click(sender As Object, e As EventArgs) Handles ButtonsetAttachObstacles.Click
        Dim quantity As Integer = Fix((attachObstaclesMaximum - attachObstaclesMinimum + 1) * Rnd() + attachObstaclesMinimum)

        For o = 1 To quantity
            pictureBox(Fix(81 * Rnd())).BackColor = Color.Black
        Next
    End Sub

    Private Sub AttachSAndTIntoMaze_Click(sender As Object, e As EventArgs) Handles ButtonAttachSAndTIntoMaze.Click
        Dim tag As Integer() = Nothing
        Dim z As Integer
        For o = 0 To 80
            If pictureBox(o).BackColor = Color.White Then
                tag(z) = o
                z += 1
            End If
        Next
        Dim S As Integer = Fix(z * Rnd() + 1)
        Dim T As Integer = Fix(z * Rnd() + 1)
        pictureBox(S).Text = "S"
        pictureBox(T).Text = "T"
    End Sub

End Class

原本預期ButtonSet_Click可以把pictureBox0~80全塗白
原本預期AttachObstacles_Click可以把pictureBox0~80隨機塗黑20~50個
原本預期AttachSAndTIntoMaze_Click可以挑出Ｔ和Ｓ
結果都沒動作