AddressOf with parameter

Question

One way or another I need to link groupID (and one other integer) to the button I am dynamically adding.. any ideas?

What I can do;

AddHandler mybutt         


        

Answer 1

There is no way to do this with AddressOf itself. What you're looking for is a lambda expression.

AddHandler myButton.Click, Function(sender, e) PrintMessage(groupId)

Private Sub PrintMessage(ByVal groupID as Integer)
    MessageBox.Show("Dynamic event happened!" & groupID .tostring)
End Sub

Answer 2

My solution:

AddHandler menuItemYear.Items(i).MouseUp, Sub() menu_year(2019)

Private Sub menu_year(ByVal intYear As Integer)
   'do something
End Sub

Answer 3

No problem ;-)

For example:

Private ComboActionsOnValueChanged As New Dictionary(Of ComboBox, EventHandler)

'somewhere in function
dim del = Sub(theSender, eventArgs)
           MsgBox(CType(theSender, ComboBox).Name & " test")
          End Sub
ComboActionsOnValueChanged.Add(myCombo, del)

'somewhere else
Dim delTest = ComboActionsOnValueChanged(myCombo)
RemoveHandler myCombo.SelectedValueChanged, delTest
myCombo.DataSource = someDataSource
AddHandler myCombo.SelectedValueChanged, delTest

as we expect, event won't fire after DataSource change in this place

Answer 4

The below worked for me:

Dim bStart = New Button With {.Text = "START"}
AddHandler bStart.Click, Function(sender, e) TriggerProcess(any Long value)


Private Function TriggerProcess(ByVal paramName As Long) As Boolean
 ' any processing logic
 Return True
End Function

Answer 5

There are few ways to do that depending of the complexity and number of parameters required. 1. Use Tag for adding a complex structure 2. Inherit the the Button class and add the values as class members then populate them before using it. That gives you a lot more flexibility.

If you are using web version 3. You cannot add it to Tag, but for simple values assign it to index use .Attributes.Add("name"). This gets added to the HTML tags and not the Server side. You can then use the index to access a server side structure for complex systems. 4. Use sessions to store values and store the session reference to Name attribute as described above (#3).

Answer 6

You can use delegate which very clear for your code follow as:

Define a delegate

Public Delegate Sub ControlClickDelegate(ByVal sender As Object, ByVal e As EventArgs)

Custom button class

Public Class CustomButton
    Inherits System.Windows.Forms.Button
#Region "property delegate"

    Private controlClickDelegate As ControlClickDelegate

    Public Property ClickHandlerDelegate As ControlClickDelegate
        Get
            Return controlClickDelegate
        End Get
        Set(ByVal Value As ControlClickDelegate)
            controlClickDelegate = Value
        End Set
    End Property

#End Region

    Public Sub RegisterEventHandler()
        AddHandler Me.Click, AddressOf OnClicking
    End Sub

    Private Sub OnClicking(ByVal sender As Object, e As System.EventArgs)
        If (Me.controlClickDelegate IsNot Nothing) Then
            Me.controlClickDelegate(sender, e)
        End If
    End Sub

End Class

MainForm

Public Class MainForm
    Public Sub New()

        ' This call is required by the designer.
        InitializeComponent()

        ' Add any initialization after the InitializeComponent() call.

        Me.CusButton1.ClickHandlerDelegate = AddressOf Me.btnClick
        Me.CusButton1.RegisterEventHandler()
    End Sub

    Private Sub btnClick(ByVal sender As Object, ByVal e As EventArgs)
        Me.TextBox1.Text = "Hello world"
        End Sub

End Class