Drag&drop on windows form

Public Class Form1
    Dim pic As New PictureBox
    Public drag As Boolean = False
    Public mousex, mousey As Integer

    Private Sub Form1_DragDrop(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles Me.DragDrop
        Dim pic As New PictureBox
        Dim rand As New Random



        Randomize(System.DateTime.Now.Millisecond)
        Threading.Thread.Sleep(10)
        pic.Location = New Point((500 * Rnd()), (500 * Rnd()))
        pic.BackColor = Color.FromArgb(rand.Next(0, 256), rand.Next(0, 256), rand.Next(0, 256))
        Me.Controls.Add(pic)
        AddHandler pic.MouseDown, AddressOf pic_MouseDown
        AddHandler pic.MouseMove, AddressOf pic_Mousemove
        AddHandler pic.MouseUp, AddressOf pic_Mouseup
        
    End Sub
    Private Sub Form1_DragEnter1(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles Me.DragEnter
        If e.Data.GetDataPresent("System.Windows.Forms.TreeNode", True) Then
            e.Effect = DragDropEffects.Copy
        Else
            e.Effect = DragDropEffects.None
        End If
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Me.AllowDrop = True
        TreeView1.AllowDrop = False
    End Sub

    Private Sub TreeView1_DragOver(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles TreeView1.DragOver
        e.Effect = DragDropEffects.Link
    End Sub

    Private Sub TreeView1_ItemDrag(ByVal sender As Object, ByVal e As System.Windows.Forms.ItemDragEventArgs) Handles TreeView1.ItemDrag
        DoDragDrop(e.Item, DragDropEffects.Copy)
    End Sub

    Private Sub pic_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs)
        If e.Button = Windows.Forms.MouseButtons.Left Then
            Me.Cursor = Cursors.Hand
            drag = True
            mousex = -e.X
            mousey = -e.Y
            Dim left As Integer = Me.PointToClient(MousePosition).X - sender.location.x
            Dim right As Integer = Me.PointToClient(MousePosition).Y - sender.location.y
            Dim width As Integer = Me.ClientSize.Width - (sender.width - left)
            Dim height As Integer = Me.ClientSize.Height - (sender.width - right)
            Windows.Forms.Cursor.Clip = Me.RectangleToScreen(New Rectangle(left, right, width, height))
            sender.invalidate()
        End If
    End Sub

    Private Sub pic_Mousemove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs)
        If drag Then
            Dim mposition As New Point()
            mposition = Me.PointToClient(MousePosition)
            mposition.Offset(mousex, mousey)
            sender.location = mposition
        End If
    End Sub

    Private Sub pic_Mouseup(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs)
        drag = False
        Windows.Forms.Cursor.Clip = Nothing
        Me.Cursor = Cursors.Arrow
        sender.invalidate()
    End Sub


    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Form2.Show()
        Me.Enabled = False
    End Sub

End Class