Remove Or Delete the Rectangle drawn on the PictureBox - vb.net

Question

I am currently solving a bug that will remove the created rectangle on the PictureBox. The problem is that when I click an Item on the PictureBox and Resize the windows form, the rectangle does not move on with the item selected. This is the code creating the rectangle:
Private Sub paintRectangle(pictBox As System.Windows.Forms.PictureBox, pic As Image)
If pic Is Nothing Then Exit Sub
pictBox.Image = pic
If m_rect_x = -1 And m_rect_y = -1 Then
Return
End If
Dim graphic As System.Drawing.Graphics
Dim redselpen As System.Drawing.Pen
Dim yNegative As Integer = 3
redselpen = New System.Drawing.Pen(Color.Blue)
redselpen.DashStyle = Drawing2D.DashStyle.DashDot
If pictBox.Image IsNot Nothing Then
graphic = System.Drawing.Graphics.FromImage(pictBox.Image)
graphic.DrawRectangle(redselpen, m_rect_x, m_rect_y - yNegative, SystemConfig.iRectWidth, SystemConfig.iRectHeight + 2)
pictBox.Image = pictBox.Image
End If
End Sub
After Resizing the Form, I want to remove the create a rectangle on the PictureBox.
I tried this solution but the Rectangle is still in the PictureBox.
How to remove all the drawn rectangles on the picture box? (Not on the image)
But it does not work, the rectangle is still in the picturebox.

Answer 1

Here's a simple example showing the Paint() event of a PictureBox being used to draw a rectangle that can be moved and turned on/off:
Public Class Form1
Private yNegative As Integer = 3
Private pt As New Nullable(Of Point)
Private drawRectangle As Boolean = False
Private Sub PictureBox1_Paint(sender As Object, e As PaintEventArgs) Handles PictureBox1.Paint
If drawRectangle AndAlso pt.HasValue Then
Using redselpen As New System.Drawing.Pen(Color.Blue)
redselpen.DashStyle = Drawing2D.DashStyle.DashDot
e.Graphics.DrawRectangle(redselpen, pt.Value.X, pt.Value.Y - yNegative, SystemConfig.iRectWidth, SystemConfig.iRectHeight + 2)
End Using
End If
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
pt = New Point(25, 25)
drawRectangle = True
PictureBox1.Invalidate()
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
drawRectangle = Not drawRectangle ' toggle the rectangle on/off
PictureBox1.Invalidate()
End Sub
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
pt = New Point(150, 25)
drawRectangle = True
PictureBox1.Invalidate()
End Sub
End Class