Adding items to ListView from a Class

Question

I am having trouble adding an item to a listview from one of my classes. I am missing something that is obviously over my head. If someone could help me to understand what I am missing that would be great.

I don't know how much detail I need to provide. What I am trying to do is to basic so I know I have to be missing something. I have a class that I am trying to use to add an item to a listview I have on a form. There are no errors thrown, yet nothing gets added.

I have even tried using something as simple as frmGiveaways.lstAccounts.items.add("wtf") in the class, it doesn't throw any errors, the line is processed, yet no items appear in the list.

What are some things that would keep me from being able to do this?

Here is the class

    Imports Simple_IRC_Client.Delegates
    Imports System.Text.RegularExpressions

    ''' <summary>
    ''' Handles minimal IRC server response messages.
''' </summary>

Public Class OutputMessages : Implements IDisposable

#Region " Private Members "
    Private ReadOnly ColorQuit As Color = Color.FromArgb(102, 54, 31)
    Private ReadOnly ColorPrivmsg As Color = Color.FromArgb(76, 76, 76)
    Private ReadOnly ColorTopic As Color = Color.FromArgb(176, 55, 176)
    Private ReadOnly ColorKick As Color = Color.FromArgb(199, 50, 50)
    Private ReadOnly ColorUserEvent As Color = Color.FromArgb(128, 128, 128)
    Private WithEvents _ircConnection As InitiateConnection
    Private _mainView As MainView
    Private _window As RichTextBox
#End Region

#Region " Constructor "
    Public Sub New(ByVal mainView As MainView, ByVal ircConnection As InitiateConnection)
        _mainView = mainView
        _ircConnection = ircConnection
        _window = _mainView.rtbChannelView
    End Sub
#End Region

#Region " EventArghs "

    Private Sub ServerResponse(ByVal serverResponse As String) Handles _ircConnection.ServerResponseOutputEventArghs

        ' This setting has only been added for demonstration purposes of what raw data
        ' looks like.
        If _mainView.mnuMainMenuOptionsrawData.Checked Then
            OutputResponse(_window, serverResponse, Color.Black)
            Exit Sub
        End If

        Dim parts() As String = serverResponse.Split(" "c)
        Dim address As String = parts(0)

        Select Case parts(1)
            Case "PRIVMSG" : Privmsg(address, serverResponse.Substring(indexOf(serverResponse, 3) + 1).Substring(1))
            Case "JOIN" : Join(address)
            Case "PART", "QUIT" : Quit(address)
            Case "ERROR" : Disconnected()
            Case "332" : TopicOnjoin(serverResponse.Substring(indexOf(serverResponse, 4) + 1).Substring(1))
        End Select
    End Sub
#End Region

#Region " Private"

    ''' <summary>
    ''' Outputs a GUI message on me/user Privmsg.
    ''' </summary>
    ''' <param name="address">The source of the user's local host.</param>
    ''' <param name="message">The message text.</param>
    ''' <remarks>
    ''' Displays an output message to the normalview window with correct format and colouring on Me, 
    ''' User Privmsg.
    ''' </remarks>
    Private Sub Privmsg(ByVal address As String, ByVal message As String)
        Dim outputFormat As String = String.Format("<{0}> {1}", Split(address), message)
        OutputResponse(_window, outputFormat, Color.Black)
        Select Case message
            Case "" : _ircConnection.SendMessage(String.Format("PRIVMSG " & ConnectionInformation.Channel & " :" & "{0}", Split(address)))
            Case frmGiveaways.keyword
                _ircConnection.SendMessage(String.Format("PRIVMSG " & ConnectionInformation.Channel & " :" & "recieved keyword", Split(address)))
                frmGiveaways.lstAccountsEntered.Items.Add(Split(address))
        End Select

    End Sub

    Private Sub Join(ByVal address As String)
        If Split(address) = ConnectionInformation.ChannelNick Then
            Exit Sub
        End If

        Dim outputFortmat As String = String.Format("{0} has joined the conversation.", Split(address))
        OutputResponse(_window, outputFortmat, ColorUserEvent)

        'Welcome message proof of concept
        '_ircConnection.SendMessage(String.Format("PRIVMSG " & ConnectionInformation.Channel & " :" & "Welcome, {0}", Split(address)))

    End Sub

    ''' <summary>
    ''' Outputs a GUI message on user Quitting.
    ''' </summary>
    ''' <param name="address">The source of the user's local host.</param>
    ''' <remarks>
    ''' Displays an output message to the normalview window with correct format on user Quitting with Quit message.
    ''' </remarks>
    Private Sub Quit(ByVal address As String)
        Dim outputFortmat As String = String.Format("{0} has left the conversation.", Split(address))
        OutputResponse(_window, outputFortmat, ColorUserEvent)
    End Sub

    Private Sub Disconnected()
        Dim outputFortmat As String = "Disconnected!"
        OutputResponse(_window, outputFortmat, Color.Red)
    End Sub

    Private Sub TopicOnjoin(ByVal subject As String)
        OutputResponse(_window, String.Format("The chat's topic is: {0} ", subject), Color.Black)
        NewLine()
    End Sub
#End Region

#Region " Output Response "
    ''' <summary>
    ''' Displays the servers output response message.
    ''' </summary>
    ''' <param name="control">The control name.</param>
    ''' <param name="output">The server output.</param>
    ''' <param name="color">The control output line color</param>
    ''' <remarks>
    ''' Responsible for displaying all server and user response messages.
    ''' </remarks>
    Public Sub OutputResponse(ByVal control As RichTextBox, ByVal output As String, ByVal color As Color)
        Dim outputFormat As String = String.Format("{0}", output)

        If control.InvokeRequired Then
            control.Invoke(New OutputEventHandler(AddressOf OutputResponse), control, output, color)
        Else
            Dim start = control.TextLength
            Dim length = outputFormat.Length

            With control
                .AppendText(outputFormat & Environment.NewLine)
                .ScrollToCaret()
                .Select(start, length)
                .SelectionColor = color
            End With
        End If
    End Sub

    Private Sub NewLine()
        If _window.InvokeRequired Then
            _window.Invoke(New MethodInvoker(AddressOf NewLine))
        Else
            _window.AppendText(Environment.NewLine)
        End If
    End Sub

#End Region

#Region " Functions "
    ''' <summary>
    ''' 
    ''' </summary>
    ''' <param name="s"></param>
    ''' <param name="instance"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Private Function indexOf(ByVal s As String, ByVal instance As Integer) As Integer
        Dim startAt As Integer = -1
        For x As Integer = 1 To instance
            startAt = s.IndexOf(" "c, startAt + 1)
        Next
        Return startAt
    End Function

    Private Function Split(ByVal name As String) As String
        Return name.Split("!"c)(0)
    End Function
#End Region

#Region " IDisposable "
    Public Sub dispose() Implements IDisposable.Dispose

    End Sub
#End Region

End Class

The part I am having a problem with is PrivMsg under the Region Private.

Answer 1

you could create a method on the form which receives a string to create a new LV item from the text passed:

Public Sub AddNewLVItem(txtName As String)
    Dim LVI as New ListViewItem
    LVI.Text = txtName

    LVI.Group = xxx     ' whatever other props there are

    lstaccounts.items.Add(LVI)
End Sub

or shorthand, if there are no subitems, groups etc

  lstaccounts.items.Add(New ListViewItem(txtName))

EDIT:

TYPICALLY, the form name is blank on MDI child forms only, I am not sure why that is the case here, but it obviously is. Forms are classes and SHOULD be instanced for use. They can use the old default instance method (FormName.Show) but that exists mainly for compatibility back to the VB4/5/6 days when forms were something apart from classes. The old default instance also makes it easier for tinkerers (non programmers) who dont have a clue about OOP, to get something woking easily.

First, you will need a reference to frmGiveAways with app level scope so that other classes all reference the same object. Add a module to your project (if there is not already one) and add:

Friend frmGive As frmGiveAways

(Or change the form name to something like FormGiveAways so the instance name and all the code referencing it can still use frmGiveAways).

Now, when you go to show the form in the menu:

If frmGive Is Nothing Then        ' check to see if it already exists
    frmGive = New frmGiveAways
    frmGive.Show                  ' could be a separate 'If' if needed
End if

Now there is one instance of frmGiveAways using the reference frmGive and as long as everyone uses that reference, things will work fine. In the 'Sub AddEntry' it would pay to set a break and monitor the Me.Name value for a while to make sure all the calling code is properly refactored.

HTH

Answer 2

Instead of hard coding the listview, try passing it into the sub as a parameter.

Something like this:

Private Sub Privmsg(ByVal address As String, ByVal message As String, ByRef LV as ListView)
    Dim outputFormat As String = String.Format("<{0}> {1}", Split(address), message)
    OutputResponse(_window, outputFormat, Color.Black)
    Select Case message
        Case "" : _ircConnection.SendMessage(String.Format("PRIVMSG " & ConnectionInformation.Channel & " :" & "{0}", Split(address)))
        Case frmGiveaways.keyword
            _ircConnection.SendMessage(String.Format("PRIVMSG " & ConnectionInformation.Channel & " :" & "recieved keyword", Split(address)))
            LV.Items.Add(Split(address))
    End Select

End Sub

Answer 3

The basic syntax to add items to a ListView is this:

' Create list view items
Dim item1 As New ListViewItem("Item #1", 0)
Dim item2 As New ListViewItem("Item #2", 1)
Dim item3 As New ListViewItem("Item #3", 2)

Then you can add the list view items to the list view, either individually or as a group, like this:

Adding item one-by-one:

ListView1.Items.Add(item1)
ListView1.Items.Add(item2)
ListView1.Items.Add(item3)

Adding several items at once:

ListView1.Items.AddRange(New ListViewItem() {item1, item2, item3})

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Note: The ListView1.Items.Add() and ListView1.Items.AddRange() methods both need ListViewItem objects, not string values.