CODEWITHSUNDEEP
vb.netwinformseventsuser-controls
DareDevil
DareDevil

Reputation: 5349

Adding Event Handler in VB.NET Custom Control

I have a scenario in which I have to implement a UserControl , On Clicking a button "Process" a background worker works.

I want to trigger a Function/Method of my parent form where I am going to add that UserControl upon "RunWorkerCompleted" Event.

Private Sub btnGo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnGo.Click
    Try            
        bgwFetchGiftCard.RunWorkerAsync()
    Catch ex As Exception
        WriteLog(ex)
    End Try
End Sub

Private Sub bgwFetchCard_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles bgwFetchCard.DoWork
    Try
        ds = New DataSet()
        'Call ApI Service for Denomination
        ds = APICALL()
    Catch ex As Exception
        WriteLog(ex)
    End Try
End Sub

Private Sub bgwFetchCard_RunWorkerCompleted(ByVal sender As System.Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles bgwFetchCard.RunWorkerCompleted
    If ds IsNot Nothing Then
        Result = True   
        'At This Point I Want To Raise Event          
        'RaiseEvent 
    Else
        'ShowMessage("FAIL")
    End If
End Sub

How may i achieve this?anybody kindly suggest

Upvotes: 3

Views: 3279

Answers (1)

Ňɏssa Pøngjǣrdenlarp
Ňɏssa Pøngjǣrdenlarp

Reputation: 38875

Assuming the code shown is in the UserControl, you just need to declare an event and raise it (there is nothing special to this regarding a UserControl):

Public Event SomethingIsDone (sender As Object, e as EventArgs)

...
Private Sub bgwFetchCard_RunWorkerCompleted(sender As Object, 
          e As RunWorkerCompletedEventArgs) Handles bgwFetchCard.RunWorkerCompleted
    If ds IsNot Nothing Then
        Result = True   

         RaiseEvent SomethingIsDone(Me, New EventsArgs()) 

    Else
        'ShowMessage("FAIL")
    End If
End Sub

In cases where you need to pass information in the event, define a custom EventArgs class which inherits from EventArgs add the properties you need:

Public Class SomethingDoneEventArgs
    Inherits EventArgs

    Public Property SomethingName As String

    ' convenience:
    Public Sub New(name As String)
        SomethingName = name
    End Sub
End Class

Then pass an instance of that class rather than the the generic EventArgs:

...
RaiseEvent SomethingIsDone(Me, 
           New SomethingDoneEventArgs("foo"))

Upvotes: 3

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