vb.net - 在VB中处理OpenFileDialog时出错

Question

我是VB的新手，所以我很欣赏这可能是一个愚蠢的问题。

我正在使用以下代码从本地文件系统中选择CSV文件。

    Dim openFileDialog1 As New OpenFileDialog

    openFileDialog1.InitialDirectory = "c:\uploads"
    openFileDialog1.Filter = "CSV files (*.csv)|*.csv"
    openFileDialog1.FilterIndex = 2
    openFileDialog1.RestoreDirectory = True


    If openFileDialog1.ShowDialog = Windows.Forms.DialogResult.OK Then

    End If


        '--TextField Parser is used to read the files 
        Dim parser As New FileIO.TextFieldParser(openFileDialog1.FileName)

如果未选择文件，如何正常显示此错误。

因此，实质上显示一条消息，指出“未选择文件”

先感谢您。

Answer 1

 Dim openFileDialog1 As New OpenFileDialog
    Dim strFileName As String
    openFileDialog1.InitialDirectory = "c:\uploads"
    openFileDialog1.Filter = "CSV files (*.csv)|*.csv"
    openFileDialog1.FilterIndex = 2
    openFileDialog1.RestoreDirectory = True

    If openFileDialog1.ShowDialog = Windows.Forms.DialogResult.OK Then
        strFiilename = openFileDialog1.FileName
        If strFileName <> "" Then
            'file is selected
        Dim parser As New FileIO.TextFieldParser(strFiilename)
        Else
            MsgBox("No File Selected")
        End If
    End If

我认为无需检查此strFileName，因为在您的问题中您已放置

Dim parser As New FileIO.TextFieldParser(openFileDialog1.FileName)

后

If openFileDialog1.ShowDialog = Windows.Forms.DialogResult.OK Then
endif

这将导致您的错误