vb.net - 检查文本文件是否为空

Question

我有以下代码：

Private Sub btnCreateAccount_Click(sender As Object, e As EventArgs) Handles btnCreateAccount.Click

        Dim fi As New System.IO.FileInfo(strUsersPath)
        Using r As StreamReader = New StreamReader(strUsersPath)
            Dim line As String
            line = r.ReadLine ' nothing happens after this point
            Do While (Not line Is Nothing)

                If String.IsNullOrWhiteSpace(line) Then
                    MsgBox("File is empty, creating master account")
                    Exit Do
                Else
                    MsgBox("Creating normal account")
                End If
                line = r.ReadLine

            Loop
        End Using

End Sub

我遇到了一些问题。基本上我有一个流式阅读器打开一个 .txt 文件，其中目录存储在“strUsersPath”中。我正在尝试获取代码，以便如果文件为空，它会做一件事，如果文件不为空（有用户），那么它会做另一件事。

如果我的 txt 文件中有一个用户，代码会按预期给出 msgbox（“创建普通帐户”），但是当我没有用户时，它不会给我另一个 msgbox，我似乎无法找出原因。我怀疑这是因为 IsNullOrWhiteSpace 不适合用于此目的。任何帮助将不胜感激

编辑 这是我也尝试过的代码，同样的结果，如果已经有用户，点击按钮什么也不做。

Private Sub btnCreateAccount_Click(sender As Object, e As EventArgs) Handles btnCreateAccount.Click

        Dim fi As New System.IO.FileInfo(strUsersPath)
       Using r As StreamReader = New StreamReader(Index.strUsersPath)
            Dim line As String
            line = r.ReadLine ' nothing happens after this point
            Do While (Not line Is Nothing)
                fi.Refresh()
                If Not fi.Length.ToString() = 0 Then
                    MsgBox("File is empty, creating master account") ' does not work
                    Exit Do
                Else
                    MsgBox("Creating normal account") ' works as expected
                End If
                line = r.ReadLine

            Loop
        End Using

End Sub

Answer 1

为此，您不需要 StreamReader。所有你需要的是File.ReadAllText

If File.ReadAllText(strUsersPath).Length = 0 Then
    MsgBox("File is empty, creating master account")
Else
    MsgBox("Creating normal account")
End If

Answer 2

我推荐使用这种方法

If New FileInfo(strUsersPath).Length.Equals(0) Then
    'File is empty.
Else
    'File is not empty.
End If