Сведения о проданных товарах в сети магазинов

Public Class Form1
    Private Structure Magazin
        Public Data As String
        Dim Nazvanie As String
        Dim Stoimost As Integer
    End Structure
    Dim MyMagazin(100) As Magazin
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        If TextBox1.Text = "" Or
           TextBox2.Text = "" Or
           TextBox3.Text = "" Then
            MessageBox.Show("Повторите ввод данных ", "ОШИБКА!!!", MessageBoxButtons.OK, MessageBoxIcon.Asterisk)
            GoTo zzz
        End If
        Static k As Integer 'Статическая переменная k, в начале k=0
        MyMagazin(k).Data = Trim(TextBox1.Text)
        MyMagazin(k).Nazvanie = Trim(TextBox2.Text)
        MyMagazin(k).Stoimost = Val(TextBox3.Text)
        MessageBox.Show("Данные введены", "ВНИМАНИЕ!", MessageBoxButtons.OK, MessageBoxIcon.Information)
        TextBox1.Text = ""
        TextBox2.Text = ""
        TextBox3.Text = ""
        TextBox6.Text = ""
zzz:
    End Sub
End Class

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Dim writer As String = Trim(TextBox4.Text)
        Dim knSelection As Magazin() = (MyMagazin.Where(Function(tt) tt.Data = writer)).ToArray
        If TextBox4.Text = "" Then
            MessageBox.Show("Повторите ввод данных ", "ОШИБКА!!!", MessageBoxButtons.OK, MessageBoxIcon.Asterisk)
            GoTo mmm
        End If
        If knSelection.Length > 0 Then
            Dim ss As String = ""
            For Each kn As Magazin In knSelection
                ss &= ("Отчет" & kn.Data & kn.Stoimost & vbCrLf)
 
            Next
            TextBox6.Text = ss
        Else
            MessageBox.Show("В этот день ничего не продано", "ОШИБКА!!!", MessageBoxButtons.OK, MessageBoxIcon.Asterisk)
 
        End If
mmm:
    End Sub
End Class

Private Structure Magazin
    Public Data As String
    Public Nazvanie As String
    Public Stoimost As Integer
    Public Sub New(ByVal d As String, ByVal n As String, ByVal s As Integer)
        Data = d
        Nazvanie = n
        Stoimost = s
    End Sub
End Structure
Dim MyMagazin(100) As Magazin
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
    MyMagazin(0) = New Magazin("11.05.2011", "my1", 1254)
    MyMagazin(1) = New Magazin("11.05.2011", "my2", 1254)
    MyMagazin(2) = New Magazin("11.05.2011", "my3", 1254)
    MyMagazin(3) = New Magazin("12.05.2011", "my1", 1254)
    MyMagazin(4) = New Magazin("17.05.2011", "my2", 1254)
    MyMagazin(5) = New Magazin("12.05.2011", "my3", 1254)
    MyMagazin(6) = New Magazin("17.05.2011", "my3", 1254)
    Dim thisDay As String = "11.05.2011"
    Dim allMoney As Integer() = (From mmm In MyMagazin Where mmm.Data = thisDay Select mmm.Stoimost).ToArray
    MsgBox(allMoney.Sum.ToString)
End Sub