Question

Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) _
      Handles Me.Load, Me.FormClosing
        MessageBox.Show("form_load")
End Sub


Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As FormClosingEventArgs) _
    Handles Me.FormClosing
    MessageBox.Show("form_closing")
End Sub

While closing the form I observed that the Form1_FormClosing method is fired first, and then Form1_Load second.

Why is this order chosen? Why doesn’t Form1_Load get fired/entered first, and then Form1_FormClosing second?

How does .NET choose which method to fire first, of the two that handle the same event?

Answer 1

Both method have Handles Me.FormClosing, so both methods are executed when the form is closed. There’s no particular orer they’re executed in.

When several methods handle the same event, the event calls them in the order they asked to receive events. The compiler has arbitrarily decided that the Form1_FormClosing method comes first. Try adding this code between the the two method and see if it changes again.

Private Sub Aaa(ByVal sender As Object, ByVal e As FormClosingEventArgs)
    Handles Me.FormClosing
    MsgBox("Aaa")
End Sub

On a side note, I’m surprised your code compiles as Form.Load has a different signature to Form.FormClosing.

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If you want code to execute in a particular order, only handle the event once and call other methods in order.

Private Sub Form1_Load(sender As Object, e As EventArgs)
    Handles Me.Load
    ReportLoad()
End Sub

Private Sub Form1_FormClosing(sender As Object, e As FormClosingEventArgs)
    Handles Me.FormClosing
    ReportLoad()
    MsgBox("Form1_FormClosing")
End Sub

Private Sub ReportLoad()
    MsgBox("ReportLoad")
End Sub

Handling an event in a method of a different name is misleading and confusing. I’d never have guessed that Form1_Load would be called by the FormClosing event. If you want to handle several events, or the same event of several objects, in one method, change the method name, like Form1_xxx or xxxButton_Click so that it’s clear that multiple events are being handled.