events

events

• JAAmutio

  Well, I think I misunderstood, it seems the FormClosing and FormLostFocus already exist and no need to add them. What i told is to add your own events and delegates.
  
  

• Artie Sluka

  Okay i dont know why needing delegates here., the code is working fine now, the error was sittingin my custom dgv where i had a dgv_lostfocus that was removing my navigators bindings. therefore when i clickd on the navigator, it was losing binding to the grid. but y u told me delegates now
  
  

• RC COLA

  The following is a simple example of declaring and using a delegate.

  Imports System
  
  Public Class SamplesDelegate
  
    ' Declares a delegate for a method that takes in an int and returns a String.
    Delegate Function myMethodDelegate(myInt As Integer) As [String]
  
    ' Defines some methods to which the delegate can point.
    Public Class mySampleClass
  
     ' Defines an instance method.
     Public Function myStringMethod(myInt As Integer) As [String]
       If myInt > 0 Then
        Return "positive"
       End If
       If myInt < 0 Then
        Return "negative"
       End If
       Return "zero"
     End Function 'myStringMethod
  
     ' Defines a static method.
     Public Shared Function mySignMethod(myInt As Integer) As [String]
       If myInt > 0 Then
        Return "+"
       End If
       If myInt < 0 Then
        Return "-"
       End If
       Return ""
     End Function 'mySignMethod
    End Class 'mySampleClass
  
    Public Shared Sub Main()
  
     ' Creates one delegate for each method.
     Dim mySC As New mySampleClass()
     Dim myD1 As New myMethodDelegate(AddressOf mySC.myStringMethod)
     Dim myD2 As New myMethodDelegate(AddressOf mySampleClass.mySignMethod)
  
     ' Invokes the delegates.
     Console.WriteLine("{0} is {1}; use the sign ""{2}"".", 5, myD1(5), myD2(5))
     Console.WriteLine("{0} is {1}; use the sign ""{2}"".", - 3, myD1(- 3), myD2(- 3))
     Console.WriteLine("{0} is {1}; use the sign ""{2}"".", 0, myD1(0), myD2(0))
  
    End Sub 'Main
  
  End Class 'SamplesDelegate

  
  
  

• ROLIVIER

  Public Sub NewForm(ByRef F As Form)

  F.Show()

  AddHandler F.FormClosing, AddressOf Form_Closing

  AddHandler F.LostFocus, AddressOf Form_LostFocus

  End Sub

  Public Sub Form_LostFocus(ByVal s As Object, ByVal e As System.EventArgs)

  Try

  mynav.BindingSource = Nothing

  Catch ex As Exception

  End Try

  End Sub

  Public Sub Form_Closing(ByVal s As Object, ByVal e As FormClosingEventArgs)

  mynav.BindingSource = Nothing

  End Sub

  for now i have this,, and it doesnt seem to work nicely.

  
  
  

• Alexei Moudretsov

  How do you difine the type of FormClosing and LostFocus I think they should be like

  Delegate Function ClosingDelegate(ByVal s As Object, ByVal e As FormClosingEventArgs) As [String]

  Delegate Function LostFocusDelegate(ByVal s As Object, ByVal e As System.EventArgs) As [String]

  Dim FormClosingAs New ClosingDelegate(AddressOf Form_Closing)

  Dim LostFocus As New LostFocusDelegate(AddressOf Form_LostFocus)
  

  
  

  
  
  
• events