How do I fix a custom border when dragging a form off the screen and back on? - vb.net

Question

I'm using a code to draw a custom dashed border around my textboxes and forms. If I grab the app and drag it off the screen and come back the border is all smeared and bad looking.
The only way I've been able to fix it is by using Me.Reload() event making the form reload which fixes it immediately. Which is alright but I'd rather it be fixed immediately almost to the point that you never even see it happen.
When I tried to add it into a timer it made the form blink really bad obviously.
Is there a way to use this code to detect when the app leaves the boundaries of the screen and just refresh the form only when the whole app returns within the boundaries of the monitor or monitors?
Public Function IsOnScreen(ByVal form As Form) As Boolean
Dim screens() As Screen = Screen.AllScreens
For Each scrn As Screen In screens
Dim formRectangle As Rectangle = New Rectangle(form.Left, form.Top, form.Width, form.Height)
If scrn.WorkingArea.Contains(formRectangle) Then
Return True
End If
Next
Return False
End Function
EDIT: I wanted to share the code I'm using to draw these borders in case it may actually be the issue.
Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
' This is the override paint event that will allow us to draw all our borders
addBorders(e)
End Sub
Public Sub addBorders(ByVal e As PaintEventArgs)
For Each ctl As Control In Me.Controls
Select Case True
Case TypeOf (ctl) Is TextBox
ctl.AutoSize = False
ctl.Height = 19
Dim borderRectangle As Rectangle = New Rectangle(ctl.Location, ctl.Size)
borderRectangle.Inflate(1, 1)
ControlPaint.DrawBorder(e.Graphics, borderRectangle, ctl.ForeColor, ButtonBorderStyle.Dashed)
Case TypeOf (ctl) Is ComboBox, TypeOf (ctl) Is Button
Dim borderRectangle As Rectangle = New Rectangle(ctl.Location, ctl.Size)
borderRectangle.Inflate(1, 1)
ControlPaint.DrawBorder(e.Graphics, borderRectangle, ctl.ForeColor, ButtonBorderStyle.Dashed)
>>>ControlPaint.DrawBorder(e.Graphics, e.ClipRectangle, ctl.ForeColor, ButtonBorderStyle.Dashed)<<< This is the problem!
End Select
Next
End Sub
I've tried adding TypeOf (ctl) Is Form to the second Case and that does not work and I am not sure why!
Case TypeOf (ctl) Is ComboBox, TypeOf (ctl) Is Button, TypeOf (ctl) Is Form
This code works perfect for the comboboxes and the textboxes but it does not draw the border on the form.

Answer 1

I'm answering my own question because I've finally got it working.
First of all I changed how I was drawing the border around the form.
Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
' This is the override paint event that will allow us to draw all our borders
addBorders(e)
If e.ClipRectangle.X = 0 Then
Dim dashValues As Single() = {3, 1, 3, 1}
Dim p As New Pen(btnExit.ForeColor, 1)
p.DashPattern = dashValues
e.Graphics.DrawRectangle(p, 0, 0, Me.Width - 1, Me.Height - 1)
End If
End Sub
Which worked perfect! There was still a small issue with going off the screen it would still mess the border up some so I added a Me.Refresh() code on the form_mouseup event so when the form is dropped it refreshes and fixes the problem.
Private Sub frmMain_MouseUp(sender As Object, e As MouseEventArgs) Handles Me.MouseUp
Me.Refresh()
End Sub
It's not exactly what I would have liked to have but it works way better this way than the other way.