Force Custom Event Handler First - vb.net

Question

When I create custom handlers like:
Public Class MyCustomClass
Public Sub AddHandlers()
AddHandler Form1.MouseMove, AddressOf MoveMouse
End Sub
Private Sub MoveMouse(sender As Object, e As MouseEventArgs)
MsgBox("Needs to happen first.")
End Sub
End Class
I need MoveMouse in this class to fire before any other event when the user moves their mouse over Form1.
Private Sub Form1_MouseMove(sender As Object, e As MouseEventArgs) Handles Me.MouseMove
MsgBox("Needs to happen second.")
End Sub
While writing this, I realized I could create yet another custom event handler in Form1's class, but is there any other way to ensure that MoveMouse (regardless of what class it is in) happens before Form1_MouseMove?
Thanks-
~Nic

Answer 1

Events are fired in the order in which they are declared:
So if you want your custom class to raise MouseMove on Form1 before Form1 raises the event you need to make your custom class add the handler first:
Public Class CustomClass
Public Sub OnMouseMoved(sender As Object, e As MouseEventArgs)
Console.WriteLine("Custom mouse moved")
End Sub
End Class
Public Class Form1
Public Custom As CustomClass
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Custom = New CustomClass
AddHandler MouseMove, AddressOf Custom.OnMouseMoved
AddHandler MouseMove, AddressOf OnMouseMoved
End Sub
Private Sub OnMouseMoved(sender As Object, e As MouseEventArgs)
Console.WriteLine("Form1 mouse moved")
End Sub
End Class