PictureBox MouseEnter / MouseLeave Events not Firing

Question

Create a new form with three picture boxes. This code is intended to draw a border when the mouse enters the picture box and remove it when it leaves. It is inconsistent in the results. Sometimes it draws/removes the border, sometimes it doesn't. This code is not complex. Using VS 2012.

Private Sub PictureBox_MouseEnter(sender As Object, e As EventArgs) _
    Handles PictureBox1.MouseEnter, PictureBox2.MouseEnter, PictureBox3.MouseEnter
    Dim pb As PictureBox = DirectCast(sender, PictureBox)
    pb.BorderStyle = BorderStyle.FixedSingle
    ' Debug.WriteLine("E " & pb.Name)
End Sub

Private Sub PictureBox_MouseLeave(sender As Object, e As EventArgs) _
    Handles PictureBox1.MouseLeave, PictureBox2.MouseLeave, PictureBox3.MouseLeave

    Dim pb As PictureBox = DirectCast(sender, PictureBox)
    pb.BorderStyle = BorderStyle.None
    ' Debug.WriteLine("X " & pb.Name)
End Sub

Answer 1

I could also reproduce the issue. So, expanding on the comments above about "drawing something else" instead of using the Picturebox's property, let me suggest this quick and dirty approach:

• Use a RectangleShape object, the one provided by the VisualBasic Powerpack 3.0 addon. Simply put one of those in the same form your PictureBox is in, and make it invisible (visible = false).

• The code is also easy:

  Public Class Form1
      Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
          Me.RectangleShape1.Location = New Point(Me.PictureBox1.Left - 1, Me.PictureBox1.Top - 1)
          Me.RectangleShape1.Size = New Size(Me.PictureBox1.Width + 1, Me.PictureBox1.Height + 1)
      End Sub
  
      Private Sub PictureBox1_MouseEnter(ByVal sender As Object, ByVal e As System.EventArgs) Handles PictureBox1.MouseEnter
          Me.RectangleShape1.Visible = True
      End Sub
      Private Sub PictureBox1_MouseLeave(ByVal sender As Object, ByVal e As System.EventArgs) Handles PictureBox1.MouseLeave
          Me.RectangleShape1.Visible = False
      End Sub
  End Class