FtpWebRequest returns error 550 File unavailable

Question

I have created a small windows forms application to upload the file to one of our client\'s ftp site. But the problem that I\'m having is that when I run this application on

Answer 1

In order to resolve this issue, it is required to force the System.Net.FtpWebRequest command to revert back to the old behavior of how it used to work in .Net Framework 2.0/3.5 and issue the extra CWD command before issuing the actual command.

In order to do this, the following code needs to be placed before any instance of the System.Net.FtpWebRequest class is invoked. The code below only needs to be called once, since it changes the settings of the entire application domain.

private static void SetMethodRequiresCWD()
{
        Type requestType = typeof(FtpWebRequest);
        FieldInfo methodInfoField = requestType.GetField("m_MethodInfo", BindingFlags.NonPublic | BindingFlags.Instance);
        Type methodInfoType = methodInfoField.FieldType;


        FieldInfo knownMethodsField = methodInfoType.GetField("KnownMethodInfo", BindingFlags.Static | BindingFlags.NonPublic);
        Array knownMethodsArray = (Array)knownMethodsField.GetValue(null);

        FieldInfo flagsField = methodInfoType.GetField("Flags", BindingFlags.NonPublic | BindingFlags.Instance);

        int MustChangeWorkingDirectoryToPath = 0x100;
        foreach (object knownMethod in knownMethodsArray)
        {
            int flags = (int)flagsField.GetValue(knownMethod);
            flags |= MustChangeWorkingDirectoryToPath;
            flagsField.SetValue(knownMethod, flags);
        }
 }

http://support.microsoft.com/kb/2134299