Question

我有以下代码，在保存文件时效果很好。但是当保存“到”对话框打开时，带有“保存”或“取消”选项.....当我单击取消时，我得到并且异常错误。 W.WriteLine（gradesListBox.Items（1）.ToString）我该如何解决这个问题？我已经尝试了这个但是没有随处可见。

 If result <> Windows.Forms.DialogResult.Cancel Then
        Close()
    End If

  Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Dim result As DialogResult

    'Writes txt File to C: Drive
    SaveFileDialog1.InitialDirectory = ("C:\")
    SaveFileDialog1.FileName = ("Save As...")
    SaveFileDialog1.Filter = ("Only Text Files (*.txt)|*.txt")
    SaveFileDialog1.ShowDialog()

           Dim W As New IO.StreamWriter(SaveFileDialog1.FileName, True)  ' writes specified information to save file
    W.WriteLine(lblTimeDate.Text & "             " & txtJobFileName.Text)
    W.WriteLine() 'Writes Blank Line
    W.WriteLine()

    'Formats Write to save file       
    W.WriteLine(vbTab & gradesListBox.Items(0).ToString)
    W.WriteLine(gradesListBox.Items(1).ToString)
    W.WriteLine(gradesListBox.Items(2).ToString)
    W.WriteLine(gradesListBox.Items(3).ToString)
    W.WriteLine(gradesListBox.Items(4).ToString)
    W.WriteLine(gradesListBox.Items(6).ToString)
    W.WriteLine(gradesListBox.Items(9).ToString)
    W.WriteLine(gradesListBox.Items(7).ToString)
    W.WriteLine(gradesListBox.Items(8).ToString)
    W.WriteLine(gradesListBox.Items(9).ToString)
    W.WriteLine(gradesListBox.Items(10).ToString)
    W.WriteLine()
    W.WriteLine()

Answer 1

If SaveFileDialog1.ShowDialog <> DialogResult.Cancel Then
  '  do all that stuff


End If

奇怪的是，你有一个对话框结果变量，但没有使用它。你不需要在列表框中指定每个项目（当有数百个项目时，它会变得相当繁琐）：

 For n as integer=0 to gradesListBox.items.count-1
     W.WriteLine(gradesListBox.Items(n).ToString)
 next n

如何保存文件而不抛出异常错误

1 个答案: