CODEWITHSUNDEEP
vb.netevent-handling
sachinthana87
sachinthana87

Reputation: 39

How to Pass Additional Parameters When Calling and Event VB.net

Public Event DocumentCompleted As WebBrowserDocumentCompletedEventHandler

Dim arg() As Object = {homeTeam, guestTeam}
        AddHandler browser.DocumentCompleted, New 
WebBrowserDocumentCompletedEventHandler(AddressOf DoStuff)

Private Sub DoStuff(ByVal sender As Object, ByVal e As WebBrowserDocumentCompletedEventArgs)

End Sub

How can I pass the homeTeam and guestTeam when firing the DocumentCompleted event. I want to ge the above to values to inside the Dostuff method.

Please help.

Upvotes: 3

Views: 7778

Answers (1)

Victor Zakharov
Victor Zakharov

Reputation: 26424

First of all, you cannot have this hanging in the middle of nowhere:

Dim arg() As Object = {homeTeam, guestTeam}
AddHandler browser.DocumentCompleted,
           New WebBrowserDocumentCompletedEventHandler(AddressOf DoStuff)

AddHandler probably needs to be in some Initialize method, which could be inside Sub New, after InitializeComponent, or inside Form_Load, or as soon as you expect it to be triggered (after a specific event). Notice here that you are using a default event of a native .NET component, with a default event type. In this case you cannot directly consume anything other than what it already provides, when triggered. See WebBrowser.DocumentCompleted Event on MSDN.

You can, however, override all relevant classes and have your own MyWebBrowser control and your own event, with would contain additional properties. See below example:

Public Class Form1
  Sub New()
    ' This call is required by the designer.
    InitializeComponent()

    Dim browser As New MyWebBrowser
    AddHandler browser.MyDocumentCompleted, AddressOf DoStuff
  End Sub

  Private Sub DoStuff(ByVal sender As Object, ByVal e As MyWebBrowserDocumentCompletedArgs)
    Dim guestTeam As String = e.GuestTeam 'guest team
    Dim homeTeam As String = e.HomeTeam 'and home team are both accessible
    'so you can do some processing on them
  End Sub

  Public Class MyWebBrowserDocumentCompletedArgs : Inherits WebBrowserDocumentCompletedEventArgs
    Dim _homeTeam As String
    Dim _guestTeam As String
    Public ReadOnly Property HomeTeam
      Get
        Return _homeTeam
      End Get
    End Property
    Public ReadOnly Property GuestTeam
      Get
        Return _guestTeam
      End Get
    End Property

    Sub New(url As Uri, homeTeam As String, guestTeam As String)
      MyBase.New(url)
      _homeTeam = homeTeam
      _guestTeam = guestTeam
    End Sub
  End Class

  Public Class MyWebBrowser : Inherits WebBrowser
    Public Delegate Sub MyWebBrowserDocumentCompletedEventHandler(e As MyWebBrowserDocumentCompletedArgs)
    Public Event MyDocumentCompleted As MyWebBrowserDocumentCompletedEventHandler

    Protected Overrides Sub OnDocumentCompleted(e As System.Windows.Forms.WebBrowserDocumentCompletedEventArgs)
      MyBase.OnDocumentCompleted(e)
      'homeTeam and guestTeam need to be extracted from the current instance of MyWebBrowser, and passed further
      RaiseEvent MyDocumentCompleted(New MyWebBrowserDocumentCompletedArgs(e.Url, "homeTeam", "guestTeam"))
    End Sub
  End Class
End Class

If your project is relatively small, you can indeed have those as global variables, as @Vlad suggested in the comments.

Upvotes: 1

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