Public Class Form1
    Dim DragFlag As Boolean
    Dim MemX As Integer, MemY As Integer
 
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        For a As Integer = 0 To 3
            Dim mypic As New PictureBox
            picZeichnung.Controls.Add(mypic)
            With mypic
                .Name = "pic" & a + 1
                .Size = New Size(30, 30)
                .SizeMode = PictureBoxSizeMode.StretchImage
                .BorderStyle = BorderStyle.FixedSingle
                .BackColor = Color.Green
                .Top = a * 100
                .Left = 100
                .Cursor = Cursors.SizeAll
                .Visible = True
                AddHandler .Click, AddressOf picB_clicked
                AddHandler .MouseDown, AddressOf picB_MouseD
                AddHandler .MouseMove, AddressOf picB_MouseM
                AddHandler .MouseUp, AddressOf picB_MouseU
            End With
        Next
    End Sub
 
    Private Sub picB_clicked(ByVal sender As Object, ByVal e As Object)
 
        Dim mypic As PictureBox = CType(sender, PictureBox)
 
    End Sub
 
    Private Sub picB_MouseD(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs)
        Dim mypic As PictureBox = CType(sender, PictureBox)
 
        mypic.BringToFront()
        DragFlag = True : MemX = e.X : MemY = e.Y
 
    End Sub
 
    Private Sub picB_MouseM(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs)
        Dim mypic As PictureBox = CType(sender, PictureBox)
 
        If Not DragFlag Then Exit Sub
        mypic.Left = mypic.Left + (e.X - MemX)
        mypic.Top = mypic.Top + (e.Y - MemY)
 
        Dim iHalf As Long = picZeichnung.Width / 2
        If mypic.Left > iHalf Then
            mypic.BackColor = Color.Red
            mypic.left = 100
            MsgBox("Fehler")
            Exit Sub
        Else
            mypic.BackColor = Color.Green
        End If
    End Sub
 
    Private Sub picB_MouseU(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs)
        Dim mypic As PictureBox = CType(sender, PictureBox)
        DragFlag = False
    End Sub
 
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles _
      Button1.Click
        MsgBox("Hallo")
    End Sub
 
    Private Sub picZeichnung_Click(sender As Object, e As EventArgs) Handles _
      picZeichnung.Click
 
    End Sub
 
    Private Sub picZeichnung_Paint(sender As Object, e As PaintEventArgs) _
      Handles picZeichnung.Paint
        For a As Integer = 1 To 3
            With picZeichnung.Controls("pic" & a)
                Dim iMitteH As Integer = .Left + (.Width / 2)
                Dim iMItteV As Integer = .Top + (.Height / 2)
 
                Using p As New Pen(Brushes.Green, 2)
                    e.Graphics.DrawLine(p, iMitteH - 30, iMItteV, iMitteH + 30, _
                      iMItteV)
                    e.Graphics.DrawLine(p, iMitteH, iMItteV - 30, iMitteH, _
                    iMItteV + 30)
                End Using
            End With
        Next
 
        picZeichnung.Refresh()
    End Sub
 
    Private Sub Form1_Resize(sender As Object, e As EventArgs) Handles Me.Resize
        Me.Width = 500
        Me.Height = 400
        With picZeichnung
            .Width = 400
            .Height = 300
            .Top = 50
            .Left = 50
        End With
 
    End Sub
End Class

picZeichnung.Refresh()