NullReferenceException Para el evento del boton "btn3" de Salvar me salta NullReferenceExcepetion en la linea
listaEventos.Add(objNewEvent)
y para el evento lstbox_DoubleClick, me salta para la linea
Return CType(listaEventos(lstbox.SelectedIndex), esdeveniment)
... Estoy siguiendo unos ejemplos y en los ejemplos no hay errores... Ni idea, de lo que puede ser... dejo el codigo...
Código PHP:
Public Class Form1
Dim listaEventos As ArrayList
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
lbl1.Visible = False
lbl2.Visible = False
lbl3.Visible = False
txb1.Visible = False
txb2.Visible = False
txb3.Visible = False
txb4.Visible = False
btn1.Visible = True
btn2.Visible = True
btn3.Visible = False
btn4.Visible = True
End Sub
Private Sub btn1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn1.Click
OutFirstPanel()
End Sub
Private Sub btn2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn2.Click
'If no event is selected in the ListBox then...
If lstbox.SelectedIndex = -1 Then
'Display a message
MessageBox.Show("Debes seleccionar un evento para poder borrarlo.", _
"Agenda de eventos")
'Exit this method
Exit Sub
End If
'Prompt the user to delete the selected event
If MessageBox.Show("Estas seguro de borrar el evento: " & _
SelectedEvent.titol & "?", "Agenda de eventos", _
MessageBoxButtons.YesNo, MessageBoxIcon.Question) = _
DialogResult.Yes Then
'Get the event to be deleted
Dim objEventToDelete As esdeveniment = SelectedEvent
'Remove the event from the ArrayList
listaEventos.Remove(objEventToDelete)
'Remove the event from the ListBox
lstbox.Items.Remove(objEventToDelete)
End If
End Sub
Private Sub btn3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn3.Click
CreateEvent(txb1.Text, txb2.Text, txb3.Text, txb4.Text)
OutSecondPanel()
End Sub
Private Sub lstbox_DoubleClick(ByVal sender As Object, ByVal e As System.EventArgs) Handles lstbox.DoubleClick
OutFirstPanel()
txb1.Text = SelectedEvent.inici
txb2.Text = SelectedEvent.durada
txb3.Text = SelectedEvent.titol
txb4.Text = SelectedEvent.descripcio
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn4.Click
'Clear the list
lstbox.Items.Clear()
End Sub
Public Sub CreateEvent(ByVal inici As String, _
ByVal durada As String, ByVal titol As String, ByVal descripcio As String)
'Declare a esdeveniment object
Dim objNewEvent As esdeveniment
'Create the new event
objNewEvent.inici = inici
objNewEvent.durada = durada
objNewEvent.titol = titol
objNewEvent.descripcio = descripcio
'Add the new event to the Arraylist
listaEventos.Add(objNewEvent)
'Add the new event to the ListBox control
lstbox.Items.Add(objNewEvent)
End Sub
Public ReadOnly Property SelectedEvent() As esdeveniment
Get
If lstbox.SelectedIndex <> -1 Then
Return the selected event
Return CType(listaEventos(lstbox.SelectedIndex), esdeveniment)
End If
End Get
End Property
Private Sub OutFirstPanel()
lstbox.Visible = False
lbl1.Visible = True
lbl2.Visible = True
lbl3.Visible = True
txb1.Visible = True
txb2.Visible = True
txb3.Visible = True
txb4.Visible = True
btn1.Visible = False
btn2.Visible = False
btn3.Visible = True
btn4.Visible = False
End Sub
Private Sub OutSecondPanel()
lstbox.Visible = True
lbl1.Visible = False
lbl2.Visible = False
lbl3.Visible = False
txb1.Visible = False
txb2.Visible = False
txb3.Visible = False
txb4.Visible = False
btn1.Visible = True
btn2.Visible = True
btn3.Visible = False
btn4.Visible = True
End Sub
End Class
Código PHP:
Public Structure esdeveniment
Public members
Public inici As String
Public durada As String
Public titol As String
Public descripcio As String
End Structure
