Visual studio 2010 显示文本文件中的某些项目

因此，我有一个带有菜单栏和对话框的表单。菜单栏上的显示选项有3个选项；所有的，虚构的，或非虚构的。该文本文件按书名、作者、类别（fic或非fic）、股票、价格的顺序排列。当用户单击DisplayAll时，我希望所有标题都显示在列表框中。如果他们点击非小说类，只需点击非小说类的标题，小说也是如此。这是我目前的代码：

Private Sub menuDisplay_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles menuDisplay.Click

    Dim books() As String = IO.File.ReadAllLines("Books.txt")
    Dim data() As String
    Dim allBooksTitle, allNonFicTitle, allFicTitle As String

    For i As Integer = 0 To books.Count - 1
        data = books(i).Split(","c)
        allBooksTitle = data(2)
        If data(2).Trim = "N" Then
            allNonFicTitle = data(0)
        ElseIf data(2).Trim = "F" Then
            allFicTitle = data(0)
        End If
    Next

    ' show result
    If menuDisplayAll.Checked Then
        lstBox.Items.Add(allBooksTitle)
    ElseIf menuDisplayFic.Checked Then
        lstBox.Items.Add(allFicTitle)
    ElseIf menuDisplayNonFic.Checked Then
        lstBox.Items.Add(allNonFicTitle)
    End If
End Sub

---

我不太清楚如何编写代码来显示小说或非小说类书籍的标题，以及如何在每个按钮之间刷新列表框，而不是添加到列表框中。非常感谢您的帮助

在此代码中显示数据的最佳方式是将显示代码移动到处理循环中

Private Sub menuDisplay_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles menuDisplay.Click

    Dim books() As String = IO.File.ReadAllLines("Books.txt")

    lstbox.Items.Clear() 'remove all items from the listbox

    For i As Integer = 0 To books.Count - 1
        Dim data() As String 'Moved inside to limit scope
        Dim allBooksTitle, allNonFicTitle As String

        data = books(i).Split(","c)
        allBooksTitle = data(2) 'store the two fields
        allNonFicTitle = data(0)

        If menuDisplayAll.Checked Then 'check for each item
            lstBox.Items.Add(allBooksTitle)
        ElseIf menuDisplayFic.Checked AndAlso data(2).Trim = "F" Then
            lstBox.Items.Add(allNonFicTitle) 
        ElseIf menuDisplayNonFic.Checked AndAlso data(2).Trim = "N"Then
            lstBox.Items.Add(allNonFicTitle)
        End If
    Next
End Sub

但是，如果您使用.NET3.5或更高版本，使用LINQ可能会更干净

Private Sub menuDisplay_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles menuDisplay.Click

    Dim books() As String = IO.File.ReadAllLines("Books.txt")

    lstbox.Items.Clear()
    Dim query As IEnumerable(Of String)
    If menuDisplayAll.Checked Then 'check for each item 
            query = From book As String In books let data As String() = book.Split(',') Select data(0)
    ElseIf menuDisplayFic.Checked
            query = From book As String In books let data As String() = book.Split(',')  Where data(2).Trim = "F" Select data(2)
    ElseIf menuDisplayNonFic.Checked
            query = From book As String In books let data As String() = book.Split(',')  Where data(2).Trim = "N" Select data(2)
    End If

    lstBox.Items.AddRange(query)
End Sub