FTP Explorer錯誤vb.net

Question

我嘗試此源和視頻，但連接到FTP我連接時出錯。 FTP探險家：[http://developer.mobtool.net/VisualBasic/Internet/ftp-explorer.aspx][1]

來源：

Imports System.IO 
Imports System.Net 


Public Class MainForm 
    Private Sub MainForm_Load(sender As Object, e As EventArgs) Handles MyBase.Load 
     txtServer.Select() 
    End Sub 

Private Sub btnLogin_Click(sender As Object, e As EventArgs) Handles btnLogin.Click 
    tvServer.Nodes.Item(0).Collapse() 
    LoadFTPRemote(txtServer.Text, tvServer) 
End Sub 

Public Sub LoadFTPRemote(ByVal dirpath As String, eTree As TreeView) 
    eTree.Nodes.Item(0).Nodes.Clear() 
    eTree.BeginUpdate() 
    Dim request As FtpWebRequest = DirectCast(WebRequest.Create(dirpath), FtpWebRequest) 
    request.Method = WebRequestMethods.Ftp.ListDirectory 
    request.Credentials = New NetworkCredential(txtUsername.Text, txtPassword.Text) 
    Dim response As FtpWebResponse = DirectCast(request.GetResponse(), FtpWebResponse) 
    Dim responseStream As Stream = response.GetResponseStream() 
    Dim reader As New StreamReader(responseStream) 
    Do While reader.Peek() >= 0 
     Dim nD As TreeNode = New TreeNode(reader.ReadLine()) 
     eTree.Nodes.Item(0).Nodes.Add(nD) 
    Loop 
    reader.Close() 
    response.Close() 
    eTree.Nodes.Item(0).Expand() 
    eTree.EndUpdate() 
End Sub 

Private Sub tvServer_AfterExpand(sender As Object, e As TreeViewEventArgs) Handles tvServer.AfterExpand 
    tvServer.BeginUpdate() 
    Dim Node As TreeNode = e.Node 
    For Each CNode As TreeNode In Node.Nodes 
     Dim PathBuilder As String = txtServer.Text & ProperRemoteLink(CNode.FullPath) 
     If Not Path.HasExtension(PathBuilder) Then 
      CNode.Nodes.Clear() 
      Dim request As FtpWebRequest = DirectCast(WebRequest.Create(PathBuilder), FtpWebRequest) 
      request.Method = WebRequestMethods.Ftp.ListDirectory 
      request.Credentials = New NetworkCredential(txtUsername.Text, txtPassword.Text) 
      Dim response As FtpWebResponse = DirectCast(request.GetResponse(), FtpWebResponse) 
      Dim responseStream As Stream = response.GetResponseStream() 
      Dim reader As New StreamReader(responseStream) 
      Dim strList As New List(Of String) 
      Do While reader.Peek() >= 0 
       Dim xNod As TreeNode = New TreeNode(IO.Path.GetFileName(reader.ReadLine())) 
       CNode.Nodes.Add(xNod) 
      Loop 
      reader.Close() 
      response.Close() 
     End If 
    Next 
    tvServer.EndUpdate() 
End Sub 

Public Function ProperRemoteLink(ByVal input As String) As String 
    Dim output As String = input 
    If input.StartsWith("FTP Server") Then output = input.ToString.Remove(0, 10) 
    Return output 
End Function 

Private Sub tvServer_AfterSelect(sender As Object, e As TreeViewEventArgs) Handles tvServer.AfterSelect 
    lblStatus.Text = txtServer.Text & ProperRemoteLink(e.Node.FullPath) 
End Sub 

末級

錯誤：

System.ArgumentOutOfRangeException: Specified argument was out of the range of valid values. Parameter name: index at System.Windows.Forms.TreeNodeCollection.get_Item(Int32 index) at zbmsdn.MainForm.btnLogin_Click(Object sender, EventArgs e) in c:\users\javad\documents\visual studio 2017\Projects\zbmsdn\zbmsdn\MainForm.vb:line 11 at System.Windows.Forms.ToolStripItem.RaiseEvent(Object key, EventArgs e) at System.Windows.Forms.ToolStripButton.OnClick(EventArgs e)

Answer 1

你應該嘗試，如果一個節點是做之前選擇檢查（0）.. 。

Private Sub btnLogin_Click(sender As Object, e As EventArgs) Handles btnLogin.Click 
    If tvServer.Nodes.Count > 0 Then 
     tvServer.Nodes.Item(0).Collapse() 
     LoadFTPRemote(txtServer.Text, tvServer) 
    End If 
End Sub 

這是我認爲的問題是，但是你的代碼又是非常有限的。