如何在VB

Question

在VB中使用此代码时，出现错误：

  

System.InvalidCastException：'无法将类型为'System.Collections.ArrayList'的对象转换为类型为'System.Collections.Generic.IEnumerable`1 [System.String]'。'

有人可以给我正确的用法吗？

完整代码：

Public Class Form1

    Dim OutputArray As New ArrayList
    Dim i = 0
    Dim Registrationdata 
    Dim FileName As String = Application.StartupPath & "\Output.txt"

    Private Sub IssueTicket_Click(sender As Object, e As EventArgs) Handles IssueTicket.Click
        Dim Speed As Integer
        If Integer.TryParse(Speedbox.Text(), Speed) Then
            If Speed <= 20 Or Speed > 300 Then
                MessageBox.Show("Please enter a valid speed between 20-200")
            ElseIf Registrationbox.Text() = Nothing Or Not Registrationbox.Text() Like "???? ???" Then
                MessageBox.Show("Please enter a vaild registration to continue e.g '1234 123'.")
            ElseIf Not IDBox.Text().StartsWith("9") Or Not IDBox.TextLength = 6 Or Not IsNumeric(IDBox.Text()) Then
                MessageBox.Show("Please enter a valid OfficerID starting with '9' and is 6 numbers long.")
            Else
                OutputArray.Add(Speed)
                OutputArray.Add(Registrationbox.Text())
                OutputArray.Add(IDBox.Text())
                MessageBox.Show("Ticket saved")
                i += 1
            End If
        End If
    End Sub

    Private Sub SaveToFile_Click(sender As Object, e As EventArgs) Handles SaveToFile.Click
        Registrationbox.Text() = Registrationdata
        IO.File.WriteAllLines(FileName, OutputArray)
    End Sub

End Class

Answer 1

要快速解决问题，您可以将代码更改为：

Dim OutputArray As New List(Of String)
...
OutputArray.Add(Speed.ToString())
OutputArray.Add(Registrationbox.Text())
OutputArray.Add(IDBox.Text())

您的代码存在的问题是ArrayList没有实现IEnumerable接口，而List却实现了IEnumerable接口，因此File.WriteAllText可以工作；但是List(Of String)希望所有项目均为字符串类型，因此您必须先将int转换为字符串，然后再将其推入列表。