Visual Basic

Dim grPicBox as Graphics = PicBox.CreateGraphics()
Dim bufferBmp As New Bitmap(Width, Height, grPicBox)

"In the confrontation between the stream and the rock, the stream always wins - not through strength but perseverance." (H. Jackson Brown)

Enumerators in .NET: See how to customise foreach loops with C#

Dim currentTab As Integer
Dim highestTab As Integer

Private Sub cbNext_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cbNext.Click
    Dim nextTab As Integer = currentTab + 1

    If nextTab > highestTab Then
        nextTab = 0
    End If

    TabControl1.SelectedIndex = nextTab
    currentTab = TabControl1.SelectedIndex
End Sub

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    currentTab = TabControl1.SelectedIndex
    highestTab = TabControl1.TabCount - 1
End Sub

Private Sub threadDrawingLines()
    Dim x As Integer
    Dim objPen As New Pen(Color.Blue)
    Dim grPicBox As Graphics = PictureBox1.CreateGraphics

    Try
        While (pNumberOfLines > 0)
            For x = 1 To pNumberOfLines
                grPicBox.DrawLine(objPen, Lines(x, 1), Lines(x, 2))
            Next
            UpdatePositions()
            Thread.Sleep(pSleepTime)
        End While
    Catch ex As ThreadAbortException
        grPicBox = Nothing
        objPen = Nothing
    End Try
End Sub