txt 文件如何打开

Public Class Form1

    Dim File As String

    Private Sub Button2_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button2.Click
        Dim FileNum As Integer
        Dim TempString As String, Temp As String

        TempString = "" : Temp = ""

        FileNum = FreeFile()
        If File <> "" Then
            FileOpen(FileNum, File, OpenMode.Input, OpenAccess.Default, OpenShare.Default)
            Do While Not EOF(FileNum)
                Temp = LineInput(FileNum)
                TempString = TempString & Temp & vbCrLf
            Loop
            FileClose(FileNum)
            TextBox2.Text = TempString
        End If
    End Sub

    Private Sub Button1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Button1.MouseDown
        Dim FileName As String

        Dialog1.FileName = ""
        Dialog1.Filter = "文字档​​（*. TXT）|*. TXT|所有档案 (*.*)|*.*"
        Dialog1.Title = "Select a TXT File"
        Dialog1.ShowDialog()

        FileName = Dialog1.FileName

        If FileName <> "" Then
            File = FileName
            TextBox1.Text = FileName
        End If

        FileName = "" : TextBox2.Text = ""
    End Sub

End Class