vb中读写文本文件

Dim str As String
Private Sub Command1_Click()
On Error GoTo err
    cdc.DialogTitle = "选择你要打开的文件"
    cdc.InitDir = "c:\"
    cdc.Filter = "*.txt|*.txt"
    cdc.ShowOpen
    Open cdc.FileName For Input As #1
    If LOF(1) > 0 Then
      Text1.Text = ""
     While Not EOF(1)
      x = DoEvents
      Line Input #1, str
      Text1.Text = Text1.Text + str + vbCrLf
'     Debug.Print str
     Wend
    End If
    Close #1
    Exit Sub
err:
    MsgBox "open file error"
    Unload Form1
End Sub

Private Sub Command2_Click()
On Error GoTo err
    cdc.DialogTitle = "选择你要保存的文件"
    cdc.InitDir = "c:\"
    cdc.Filter = "*.txt|*.txt"
    cdc.ShowSave
    Open cdc.FileName For Output As #2
    Print #2, Text1.Text
    Close #2
    Exit Sub
err:
    MsgBox "open file error"
    Unload Form1
End Sub