Hi namojainashis...,

Refer below article. The exception is handled in the Catch block.

If any error comes you can log the error in the catch block.

Uploading Files to FTP Server programmatically in ASP.Net using C# and VB.Net

If you want to check for particular error then you have to check condition with StatusCode.

For different StatusCode refer below link.

FtpStatusCode Enum 

Example

C#

FtpWebResponse response = (FtpWebResponse)request.GetResponse();
if ((int)response.StatusCode == 200)
{
    // Success.
}
else
{
    // Failure.
}
response.Close();

VB.Net

Dim response As FtpWebResponse = DirectCast(request.GetResponse(), FtpWebResponse)
If CInt(response.StatusCode) = 200 Then
    ' Success.
Else
    ' Failure.
End If
response.Close()