无法访问外部类型的非静态成员

Question

The error is in TextBox1.Text and Label2.Text are the "non-static members of outer type".

Everything else is in good working order except for TextBox1.Text and Label2.Text.

The program should take a pre existing ftp file(server side) and copy it to a file specified in TextBox1.Text (client side).

Error code:

Cannot access a non-static member of outer type 'FTPDownload._Default' via nested type 'FTPDownload._Default._Default' C:\\Users\\user\\path\\Default.aspx.cs

Default.aspx

<center><table><tr><td align="center"><br /><br />
    <asp:TextBox ID="TextBox1" runat="server">C:/</asp:TextBox></td></tr><tr><td align="center"><br />
    <asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" /></td></tr><tr><td align="center"><br /><br />
    <asp:Label ID="Label2" runat="server" Text=""></asp:Label>
</td></tr></table></center>

Default.aspx.cs

[System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name = "FullTrust")]
public partial class _Default : System.Web.UI.Page
{
        private string host = "ftp://mysite.com";
        private string user = "ftp72390003-0";
        private string pass = "pass";
        private FtpWebRequest ftpRequest = null;
        private FtpWebResponse ftpResponse = null;
        private Stream ftpStream = null;
        private int bufferSize = 2048;
    protected void Button1_Click(object sender, EventArgs e)
    {
        download("GraphingPlanets.exe", TextBox1.Text + "GraphingPlanets.exe");
    }
    public void download(string remoteFile, string localFile)
    {
        try
        {
            ftpRequest = (FtpWebRequest)FtpWebRequest.Create(new Uri(host + "/" + remoteFile));
            ftpRequest.Credentials = new NetworkCredential(user, pass);
            ftpRequest.UseBinary = true;
            ftpRequest.UsePassive = true;
            ftpRequest.KeepAlive = true;
            ftpRequest.Method = WebRequestMethods.Ftp.DownloadFile;
            ftpResponse = (FtpWebResponse)ftpRequest.GetResponse();
            ftpStream = ftpResponse.GetResponseStream();
            FileStream localFileStream = new FileStream(localFile, FileMode.Create);
            byte[] byteBuffer = new byte[bufferSize];
            int bytesRead = ftpStream.Read(byteBuffer, 0, bufferSize);
            try
            {
                while (bytesRead > 0)
                {
                    localFileStream.Write(byteBuffer, 0, bytesRead);
                    bytesRead = ftpStream.Read(byteBuffer, 0, bufferSize);
                }
            }
            catch (Exception ex) { Label2.Text = "Write: " + ex.ToString; }
            localFileStream.Close();
            ftpStream.Close();
            ftpResponse.Close();
            ftpRequest = null;
        }
        catch (Exception ex) { Label2.Text = "Total: " + ex.ToString; }
    }

Answer 1

C# isn't like Java. An inner class doesn't carry an implicit reference to the outer instance used to create it. You will have to pass the reference explicitly to the inner class instance so that it can use it.

Alternatively, if you did not mean to create the inner "_Default" class, but instead to just add code to the outer "_Default" class, you should fix the code so that it doesn't have the nested class.