Public Class Form1
    Private Sub Button1_Click(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button1.Click
        If (ListBox1.SelectedIndex.ToString <> -1) Then
            Dim s As String = ListBox1.Items(ListBox1.SelectedIndex.ToString)
            Dim ar() As String
            ar = Split(s, ",")
            TextBox1.Text = ar(0)
            TextBox2.Text = ar(1)
            TextBox3.Text = ar(2)
            TextBox4.Text = CInt(TextBox4.Text) + CInt(ar(2))
        End If
    End Sub
    Private Sub Button2_Click(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button2.Click
        Dim s As String
        s = TextBox1.Text + "," + TextBox2.Text + "," + TextBox3.Text
        ListBox1.Items.Add(s)
    End Sub
    Private Sub Button3_Click(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button3.Click
        Dim i As Integer
        Dim ar(ListBox1.Items.Count - 1) As String
        Dim f() As String
        Dim cnt As Integer = 0
        For i = 0 To ListBox1.Items.Count - 1
            f = Split(ListBox1.Items(i), ",")
            If (TextBox1.Text <> f(0)) Then
                ar(cnt) = ListBox1.Items(i)
                cnt = cnt + 1
            End If
        Next
        ListBox1.Items.Clear()
        For i = 0 To cnt - 1
            ListBox1.Items.Add(ar(i))
        Next
    End Sub
    Private Sub Button4_Click(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button4.Click
        Dim i As Integer
        Dim ar(ListBox1.Items.Count - 1) As String
        Dim f() As String
        Dim cnt As Integer = 0
        For i = 0 To ListBox1.Items.Count - 1
            f = Split(ListBox1.Items(i), ",")
            If (TextBox1.Text <> f(0)) Then
                ar(cnt) = ListBox1.Items(i)
                cnt = cnt + 1
            Else
                ar(cnt) = TextBox1.Text + "," + TextBox2.Text + "," + TextBox3.Text
                cnt = cnt + 1
            End If
        Next
        ListBox1.Items.Clear()
        For i = 0 To cnt - 1
            ListBox1.Items.Add(ar(i))
        Next
    End Sub
    Private Sub Button5_Click(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button5.Click
        Dim i As Integer
        Dim s As String = ""
        For i = 0 To ListBox1.Items.Count - 1
            s &= ListBox1.Items(i) & Chr(10)
        Next
        MsgBox(s)
    End Sub
End Class