将新书添加到数组Books（）

Question

我必须将新书添加到数组Books（）中。我现在需要一个文本文件来填充数组，我需要ReDim Preserve来为数组添加一本新书。这是ReDim和For循环我有一个功能来执行此操作，但它无法正常工作。关于如何做到这一点的任何想法。

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

    Dim newBook As Book
    newBook = EmptyBook()

    ReDim Preserve Books(Books.Count)

    For i As Integer = 0 To Books.Count - 1
        Books(i) = newBook
    Next

End Sub

Function EmptyBook() As Book
    Dim Answer As Book
    With Answer
        .title = txtTitle.Text
        .authorLastName = txtAuthor.Text
        .year = CInt(txtYear.Text)
        .value = CDec(txtValue.Text)
    End With
    Return Answer
End Function

Answer 1

尝试以下方法：

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

Dim newBook As Book
newBook = EmptyBook()

if Books is nothing then
  ReDim Books(0)
else
  ReDim Preserve Books(Books.GetUpperBound(0) + 1)
end if

Books(Books.GetUpperBound(0)) = newBook 

End Sub