Question

我在vb中有这段代码：

Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles browsebtn.Click
    OpenFileDialog1.Filter = "Text Files|*.txt"
    OpenFileDialog1.Title = "Select Log File"
    If OpenFileDialog1.ShowDialog = Windows.Forms.DialogResult.OK Then
        Dim filename As String = OpenFileDialog1.FileName
        Using streamreader As New StreamReader(filename)
            While streamreader.Read
                Dim line As String = streamreader.ReadLine()
                Dim date1 As String = line.Substring(6, 6)
                Dim writer = New StreamWriter("c:\" + date1 + ".txt")
                writer = File.AppendText(line)
                writer.Close()
            End While
        End Using

    End If
End Sub
End Class

当我运行它时，它会给我一个错误：

"startIndex cannot be larger than length of string."

我做错了什么？

Answer 1

有几条注释没有意义，就像循环结束时发生的错误或者检查字符串长度会导致文件访问错误一样。试试这个：

  Dim Line as String           
  Dim Date1 As String

  While streamreader.Read
     Line = streamreader.ReadLine()
     If Line.Length > 12 Then
         date1  = line.Substring(6, 6)
         Using sw As New StreamWriter("c:\" + date1 + ".txt")
             sw.Write(line)
         End Using
     End If
  End While

vb.net appendline substring错误

1 个答案: