WithEvents Error in Visual Studio 2015?

Question

I probably ran into a Visual Studio 2015 problem. If you define three handlers for the same event using keywords WithEventsand Handlesone of the handlers will not be called. I traced this behavior in our software and wrote the following WinForms sample project.

Public Class MainBase1
    Inherits Form

    Protected WithEvents Button1 As Button
    Protected TextBox1 As TextBox

    Public Sub New()
        SuspendLayout()

        Text = "WithEvents Test"
        ClientSize = New Size(300, 300)

        Button1 = New Button()
        Button1.Location = New Point(10, 10)
        Button1.Size = New Size(100, 25)
        Button1.Text = "Button1"
        Controls.Add(Button1)

        TextBox1 = New TextBox()
        TextBox1.Location = New Point(10, 50)
        TextBox1.Multiline = True
        TextBox1.Size = New Size(280, 240)
        Controls.Add(TextBox1)

        ResumeLayout(False)
        PerformLayout()
    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        TextBox1.Text &= "MainBase1: Button click handled." & vbNewLine
    End Sub
End Class


Public Class MainBase2
    Inherits MainBase1

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        TextBox1.Text &= "MainBase2: Button click handled." & vbNewLine
    End Sub
End Class


Public Class Main
    Inherits MainBase2

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        TextBox1.Text &= "Main: Button click handled." & vbNewLine
    End Sub
End Class

After clicking Button1 Textbox1contains

MainBase1: Button click handled.
Main: Button click handled.

If I compile the same sample in Visual Studio 2012, I get

MainBase1: Button click handled.
MainBase2: Button click handled.
Main: Button click handled.

Has anyone encountered this problem? Or am I missing something?

Answer 1

This error still persists. Here is my solution.

MainBase1 Protected Overridable. Handles, MyBase.

, .

Public Class MainBase1
    Inherits Form

    Protected WithEvents Button1 As Button
    Protected TextBox1 As TextBox

    Public Sub New()
        SuspendLayout()

        Text = "WithEvents Test"
        ClientSize = New Size(300, 300)

        Button1 = New Button()
        Button1.Location = New Point(10, 10)
        Button1.Size = New Size(100, 25)
        Button1.Text = "Button1"
        Controls.Add(Button1)

        TextBox1 = New TextBox()
        TextBox1.Location = New Point(10, 50)
        TextBox1.Multiline = True
        TextBox1.Size = New Size(280, 240)
        Controls.Add(TextBox1)

        ResumeLayout(False)
        PerformLayout()
    End Sub

    Protected Overridable Sub Button1_Click(sender As Object, e As EventArgs) _
    Handles Button1.Click
        TextBox1.Text &= "MainBase1: Button click handled." & vbNewLine
    End Sub
End Class


Public Class MainBase2
    Inherits MainBase1

    Protected Overrides Sub Button1_Click(sender As Object, e As EventArgs)
        MyBase.Button1_Click(sender, e)
        TextBox1.Text &= "MainBase2: Button click handled." & vbNewLine
    End Sub
End Class


Public Class Main
    Inherits MainBase2

    Protected Overrides Sub Button1_Click(sender As Object, e As EventArgs)
        MyBase.Button1_Click(sender, e)
        TextBox1.Text &= "Main: Button click handled." & vbNewLine
    End Sub
End Class