如何与arraylists中的结构进行交互？

Question

我需要帮助尝试学习如何使结构与arraylists一起工作。我正在尝试制作一个允许用户输入帐户的程序。这是一个家庭作业，教授想要使用arraylists而不是list。

该帐户包括名字，姓氏，帐号和余额。用户可以使用previoous和next按钮来浏览帐户，并使用新的，保存和添加按钮来创建或更改帐户。我很好奇我如何在整个arraylist中循环，以及我如何在某个索引处调用结构中的某个变量。例如，我想在firstnametextbox中显示第一个名称。当我按下“下一步”按钮时，如何使FirstNameTextbox.Text ='帐户结构的名字，在第二个arraylist点'

这是我的代码

http://ideone.com/s1DlGn

Public Class AccountInformationForm

Dim objaccount As account
Dim accounts As New ArrayList

Public Structure account

    Public RecordNum As Integer
    Public FirstName As String
    Public LastName As String
    Public balance As Double
    Public account As Integer
End Structure

Private Sub AccountInformationForm_Load(sender As Object, e As EventArgs) Handles MyBase.Load

    'Example account to start off with
    objaccount.RecordNum = 0
    objaccount.FirstName = "Jesus"
    objaccount.LastName = "Christ"
    objaccount.balance = 100
    objaccount.account = 1

    accounts.Add(objaccount)


    'Display First Record
    firstTextBox.Text = objaccount.FirstName
    lastTextBox.Text = objaccount.LastName
    balanceTextBox.Text = objaccount.balance
    accountTextBox.Text = objaccount.account



End Sub


Private Sub nextButton_Click(sender As Object, e As EventArgs) Handles nextButton.Click


    objaccount.RecordNum += 1

    If objaccount.RecordNum > accounts.Count Then
        objaccount.RecordNum = 0

    End If


    'Display Current Record
    firstTextBox.Text = objaccount.FirstName
    lastTextBox.Text = objaccount.LastName
    balanceTextBox.Text = objaccount.balance
    accountTextBox.Text = objaccount.account
End Sub


Private Sub previousButton_Click(sender As Object, e As EventArgs) Handles previousButton.Click
    'Before paging away, save the current form data in the current record

    objaccount.RecordNum -= 1

    'Check for wrap around
    If objaccount.RecordNum < 0 Then 'the first, zeroth, element = index of 0
        objaccount.RecordNum = accounts.Count



    End If


    firstTextBox.Text = objaccount.FirstName
    lastTextBox.Text = objaccount.LastName
    balanceTextBox.Text = objaccount.balance
    accountTextBox.Text = objaccount.account




End Sub

Private Sub btnAdd_Click(sender As Object, e As EventArgs) Handles btnAdd.Click

    Dim upper As Integer = accounts.Count
    objaccount.RecordNum = (upper + 1)



    If firstTextBox.Text = "" Then
        MsgBox("Please enter a name")
    Else
        objaccount.FirstName = firstTextBox.Text
    End If

    If lastTextBox.Text = "" Then
        MsgBox("Please enter a name")
    Else
        objaccount.LastName = lastTextBox.Text
    End If

    If balanceTextBox.Text = "" Then
        MsgBox("Please enter a name")
    Else
        objaccount.balance = balanceTextBox.Text
    End If

    If accountTextBox.Text = "" Then
        MsgBox("Please enter a name")
    Else
        objaccount.account = accountTextBox.Text
    End If

    accounts.Add(objaccount)


    firstTextBox.Clear()
    lastTextBox.Clear()
    balanceTextBox.Clear()
    accountTextBox.Clear()

End Sub

Private Sub Save_Click(sender As Object, e As EventArgs) Handles Save.Click




    Dim upper As Integer = accounts.Count
    objaccount.RecordNum = (upper + 1)


    If firstTextBox.Text = "" Then
        MsgBox("Please enter a name")
    Else
        objaccount.FirstName = firstTextBox.Text
    End If

    If lastTextBox.Text = "" Then
        MsgBox("Please enter a name")
    Else
        objaccount.LastName = lastTextBox.Text
    End If

    If balanceTextBox.Text = "" Then
        MsgBox("Please enter a name")
    Else
        objaccount.balance = balanceTextBox.Text
    End If

    If accountTextBox.Text = "" Then
        MsgBox("Please enter a name")
    Else
        objaccount.account = accountTextBox.Text
    End If

    accounts.Add(objaccount)


End Sub

Private Sub btnNew_Click(sender As Object, e As EventArgs) Handles btnNew.Click
    firstTextBox.Clear()
    lastTextBox.Clear()
    balanceTextBox.Clear()
    accountTextBox.Clear()


    Dim upper As Integer = accounts.Count
    objaccount.RecordNum = (upper + 2)
    accountTextBox.Text = objaccount.RecordNum

End Sub

结束班