Visual Basic.NET - Pintar sobre un picture box

Hola foro alguien sabe como puedo pintar un grafico rectangulo, circulo o lo ke sea sobre un picture box?.... lo hago pero el grafico siempre se ponedebajo del picture box... alguien tiene alguna idea? lo unico ke he logrado es escribir sobre el picture box pero no puedo lograr ke se dibuje sobre él. espero me puedan ayudar.. mil gracias.

Imports System.Drawing
Imports System.Drawing.Drawing2D


Dim gp As Graphics

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

gp = PictureBox1.CreateGraphics
Dim pn As New Pen(Color.Orange, 2)
gp.DrawRectangle(pn, New Rectangle(2, 2, 100, 100))

End sub

Gracias por el codigo. Lo modifike para ke pueda guardar varios rectangulos pero al momento de resize se borran, Alguna sugurencia para conservar los N rectangulos y las posiciones de los mismos ?

Imports System.Drawing
Imports System.Drawing.Drawing2D

Public Class Dibuja
Inherits Form
Friend WithEvents PictureBox1 As System.Windows.Forms.PictureBox
Dim gp As Graphics
Sub New()
InitializeComponent()
End Sub
Private Sub InitializeComponent()
Dim resources As System.ComponentModel.ComponentResourceManager = New System.ComponentModel.ComponentResourceManager(GetType(Dibuja))
Me.PictureBox1 = New System.Windows.Forms.PictureBox
CType(Me.PictureBox1, System.ComponentModel.ISupportInitialize).BeginInit()
Me.SuspendLayout()
'
'PictureBox1
'
Me.PictureBox1.Image = CType(resources.GetObject("PictureBox1.Image"), System.Drawing.Image)
Me.PictureBox1.Location = New System.Drawing.Point(0, 29)
Me.PictureBox1.Name = "PictureBox1"
Me.PictureBox1.Size = New System.Drawing.Size(292, 232)
Me.PictureBox1.TabIndex = 1
Me.PictureBox1.TabStop = False
'
'Dibuja
'
Me.ClientSize = New System.Drawing.Size(292, 273)
Me.Controls.Add(Me.PictureBox1)
Me.Name = "Dibuja"
CType(Me.PictureBox1, System.ComponentModel.ISupportInitialize).EndInit()
Me.ResumeLayout(False)

End Sub
Protected Overrides Sub OnResize(ByVal e As System.EventArgs)
PictureBox1.Width = Me.Width
PictureBox1.Height = Me.Height
PictureBox1.SizeMode = PictureBoxSizeMode.StretchImage
End Sub
Public Sub DibujaEn(ByVal X As Integer, ByVal Y As Integer)
gp = PictureBox1.CreateGraphics
Dim pn As New Pen(Color.Orange, 2)
gp.DrawRectangle(pn, New Rectangle(X, Y, 170, 50))
gp.FillRectangle(Brushes.Red, New Rectangle(X, Y, 170, 50))
End Sub

Private Sub PictureBox1_MouseUp(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseUp
DibujaEn(e.X, e.Y)
End Sub
End Class

con el siguiente codigo logro tener llebar un control de los puntos de cada uno de los rectangulos dibujados, les pongo un label, y una escala cuando se le da un resize manda un msgbox con el % de incriemento por cada lado.... y tiene 2 botones uno ke dice Repintar para volver a pintar los rectangulos desde del redraw (esto por ke no se cual evento se dispara despues del resize) y otro ke sirve para Eliminar (esto por ke no se ejecuta el evento on keyup, o keydown, esta raro) y sirve para eliminar rectangulos, solo le ingresamos el label del rectangulo ke se kiere eliminar nos confirma y se elimina del arreglo de rectangulos, se tiene ke dar repintar para volver a pintar los rectangulos y tambien un resize por ke si no aparecen aun los rectangulos eliminados.
Existen dos tipos de rectangulos Horizontal (click izquierdo) y Vertical (click Derecho). Lo ke kiero ahora es ke el Boton de Eliminar funciones directamente con la tecla Supr o Del por ke el evento keyup, kydown no se dispara y ke el Repintar se llame o se ejecute automaticamente despues del resize.... y que no se pueda agregar un rectangulo en donde ya existe uno.... alguna sugerencia?

Imports System.Drawing
Imports System.Drawing.Drawing2D

Public Class Dibuja
Inherits Form
Dim I As Integer = 0
Dim Arr(100, 2) As Integer
Dim Ancho As Integer = 0
Dim Alto As Integer = 0
Dim CajaAncho As Single = 0.1
Dim CajaAlto As Single = 0.035
Friend WithEvents PictureBox1 As System.Windows.Forms.PictureBox
Friend WithEvents Button1 As System.Windows.Forms.Button
Friend WithEvents Button2 As System.Windows.Forms.Button
Dim gp As Graphics
Sub New()
InitializeComponent()
PictureBox1.Width = Me.Width
PictureBox1.Height = Me.Height
PictureBox1.SizeMode = PictureBoxSizeMode.StretchImage
End Sub
Private Sub InitializeComponent()
Dim resources As System.ComponentModel.ComponentResourceManager = New System.ComponentModel.ComponentResourceManager(GetType(Dibuja))
Me.PictureBox1 = New System.Windows.Forms.PictureBox
Me.Button1 = New System.Windows.Forms.Button
Me.Button2 = New System.Windows.Forms.Button
CType(Me.PictureBox1, System.ComponentModel.ISupportInitialize).BeginInit()
Me.SuspendLayout()
'
'PictureBox1
'
Me.PictureBox1.Image = CType(resources.GetObject("PictureBox1.Image"), System.Drawing.Image)
Me.PictureBox1.Location = New System.Drawing.Point(0, 29)
Me.PictureBox1.Name = "PictureBox1"
Me.PictureBox1.Size = New System.Drawing.Size(295, 247)
Me.PictureBox1.TabIndex = 1
Me.PictureBox1.TabStop = False
'
'Button1
'
Me.Button1.Location = New System.Drawing.Point(0, 0)
Me.Button1.Name = "Button1"
Me.Button1.Size = New System.Drawing.Size(75, 23)
Me.Button1.TabIndex = 2
Me.Button1.Text = "Repintar"
Me.Button1.UseVisualStyleBackColor = True
'
'Button2
'
Me.Button2.Location = New System.Drawing.Point(81, 0)
Me.Button2.Name = "Button2"
Me.Button2.Size = New System.Drawing.Size(75, 23)
Me.Button2.TabIndex = 3
Me.Button2.Text = "Eliminar"
Me.Button2.UseVisualStyleBackColor = True
'
'Dibuja
'
Me.ClientSize = New System.Drawing.Size(292, 273)
Me.Controls.Add(Me.Button2)
Me.Controls.Add(Me.Button1)
Me.Controls.Add(Me.PictureBox1)
Me.Name = "Dibuja"
CType(Me.PictureBox1, System.ComponentModel.ISupportInitialize).EndInit()
Me.ResumeLayout(False)

End Sub
Protected Overrides Sub OnResize(ByVal e As System.EventArgs)

Ancho = ((Me.Width - PictureBox1.Width) * 100) / PictureBox1.Width
Alto = ((Me.Height - PictureBox1.Height) * 100) / PictureBox1.Height
Dim W As Integer
For W = 0 To I - 1
Arr(W, 0) *= (Ancho / 100) + 1
Arr(W, 1) *= (Alto / 100) + 1
Next W

PictureBox1.Width = Me.Width
PictureBox1.Height = Me.Height
PictureBox1.SizeMode = PictureBoxSizeMode.StretchImage

MsgBox("Alto= " & Alto & " Ancho= " & Ancho)
End Sub

Public Sub DibujarCajas(Optional ByVal Tipo As Integer = 0, Optional ByVal X As Integer = 0, Optional ByVal Y As Integer = 0)
gp = PictureBox1.CreateGraphics

Dim pn As New Pen(Color.Orange, 2)
Dim W As Integer
If I = 1 Then
If Tipo = 0 Then
gp.DrawRectangle(pn, New Rectangle(X, Y, PictureBox1.Width * CajaAncho, PictureBox1.Height * CajaAlto))
gp.FillRectangle(Brushes.Red, New Rectangle(X, Y, PictureBox1.Width * CajaAncho, PictureBox1.Height * CajaAlto))
gp.DrawString(Str(W), Font, Brushes.Cyan, Arr(W, 0), Arr(W, 1))
ElseIf Tipo = 1 Then
gp.DrawRectangle(pn, New Rectangle(X, Y, PictureBox1.Width * CajaAlto, PictureBox1.Height * CajaAncho))
gp.FillRectangle(Brushes.Red, New Rectangle(X, Y, PictureBox1.Width * CajaAlto, PictureBox1.Height * CajaAncho))
gp.DrawString(Str(W), Font, Brushes.Cyan, Arr(W, 0), Arr(W, 1))
End If

Else 'entonces ya hay cajas antes y recorremos el arreglo de las N cajas
For W = 0 To I - 1
If Arr(W, 2) = 0 Then
gp.DrawRectangle(pn, New Rectangle(Arr(W, 0), Arr(W, 1), PictureBox1.Width * CajaAncho, PictureBox1.Height * CajaAlto))
gp.FillRectangle(Brushes.Red, New Rectangle(Arr(W, 0), Arr(W, 1), PictureBox1.Width * CajaAncho, PictureBox1.Height * CajaAlto))
gp.DrawString(Str(W), Font, Brushes.Cyan, Arr(W, 0), Arr(W, 1))
ElseIf Arr(W, 2) = 1 Then
gp.DrawRectangle(pn, New Rectangle(Arr(W, 0), Arr(W, 1), PictureBox1.Width * CajaAlto, PictureBox1.Height * CajaAncho))
gp.FillRectangle(Brushes.Red, New Rectangle(Arr(W, 0), Arr(W, 1), PictureBox1.Width * CajaAlto, PictureBox1.Height * CajaAncho))
gp.DrawString(Str(W), Font, Brushes.Cyan, Arr(W, 0), Arr(W, 1))
End If

Next W
End If

End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
DibujarCajas()
End Sub

Private Sub PictureBox1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseDown
If e.Button = Windows.Forms.MouseButtons.Left Then
Arr(I, 0) = e.X
Arr(I, 1) = e.Y
Arr(I, 2) = 0
I += 1
DibujarCajas(0, e.X, e.Y)
ElseIf e.Button = Windows.Forms.MouseButtons.Right Then
Arr(I, 0) = e.X
Arr(I, 1) = e.Y
Arr(I, 2) = 1
I += 1
DibujarCajas(1, e.X, e.Y)
End If
End Sub

Private Sub Dibuja_KeyUp(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyUp
If e.KeyCode = Keys.A Then
Dim Del As Integer
Del = InputBox("Escribe la caja a eliminar: ", "Eliminar", "-1")
If Not Del = -1 Then
'cancelado
ElseIf Del <= I Then
If MsgBox("Seguro de eliminar la caja: " & Del, MsgBoxStyle.YesNo) = MsgBoxResult.Yes Then
Dim Z As Integer
For Z = Del To I - 1
Arr(Z, 0) = Arr(Z + 1, 0) 'x
Arr(Z, 1) = Arr(Z + 1, 1) 'y
Arr(Z, 2) = Arr(Z + 1, 2) 'tipo
I -= 1
Next
End If
End If
End If
End Sub

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click

Dim Del As Integer
Del = InputBox("Escribe la caja a eliminar: ", "Eliminar", "-1")
If Del = -1 Then
'cancelado
ElseIf Del <= I Then
If MsgBox("Seguro de eliminar la caja: " & Del, MsgBoxStyle.YesNo) = MsgBoxResult.Yes Then
Dim Z As Integer
For Z = Del To I - 1
Arr(Z, 0) = Arr(Z + 1, 0) 'x
Arr(Z, 1) = Arr(Z + 1, 1) 'y
Arr(Z, 2) = Arr(Z + 1, 2) 'tipo

Next
I -= 1
End If
End If

End Sub
End Class