Version: 2.0.2.0
Add comprehensive secure file transfer capabilities to any application supporting ActiveX controls.
Frequently Asked Questions
Q: How do I deploy Excel spreadsheets that use PowerTCP ActiveX controls?
A: Unfortunately, there is no consistent model for 3rd party component support across Office products and versions. The recommended usage in Excel is to use the product as a reference rather than inserting it as a control. Also, if the spreadsheet ever had a PowerTCP control inserted at any previous time, that data was cached by Excel and a new spreadsheet will be required. When deploying to users, please refer to "Distribution under Internet Information Server" in the documentation for instructions as the technique is the same.
Back to Top
Q: How do I dialup to the Internet using the FTP Control?
A: If an Internet connection is not active, and you use the FTP Control to start a file transfer, the dialup dialog will automatically appear for the user to initiate a dialup session. If you need greater control of dialup services within your program, the PowerTCP Winsock Tool includes a RAS control for this purpose.
Back to Top
Q: How do I remove directories and delete files on the server?
A: The RemoveDirectory() and Delete() methods are used for this purpose.
Back to Top
Q: How is the PowerTCP Mail Tool different from the competition?
A: Dart’s primary design goal is ease-of-use while preserving capability and flexibility, and the Mail Tool is probably the best example of this duality. We do this by segmenting and simplifying the problem into a rich object model that is intuitive, but is only referenced if needed by the developer. For example, the POP3 control dynamically creates a collection of Message objects when it downloads messages. By creating the Message objects, we eliminate your need to understand anything about the how the transfer or decoding took place, and you only need to write enough code to pick out those features of the message that are relevant to your solution.
Back to Top
Q: How will I be affected if I have installed Windows XP SP2?
A: Microsoft Windows XP SP2 is a large update to the Windows XP operating system. The focus of this update is to tighten system security. One of those features is the built-in firewall. By default, Microsoft will turn on the firewall and block all applications from communicating over the Internet. As most PowerTCP products are designed for building Internet applications, those applications may be blocked from accessing the network. The solution to this problem, as it is for any application that needs to access the network, is to grant permission using Microsoft’s configuration utility. Instructions on using the Microsoft firewall are at http://www.microsoft.com/windowsxp/using/security/internet/sp2_wfintro.mspx, and more information about manual network security configuration is available by reading Microsoft Knowledge Base Article - 842242 . Also, Microsoft will disallow using ActiveX controls in Internet Explorer by default. It your web application uses PowerTCP ActiveX controls in IE, your users will have to manually adjust their security settings to allow ActiveX usage. If you find any other problems with SP2 and PowerTCP products, please contact Dart support at support@dart.com.
Back to Top
Q: I am dynamically instantiating your ActiveX control in .NET but when I deploy my application I am always getting a trial message.
A: There is a known bug in the .NET Framework that prevents ActiveX components from being licensed properly when they are dynamically instantiated. Currently, the workaround is to place the control on a form and instantiate an instance of that form without actually showing it. Microsoft is aware of the problem and we are currently looking at other workarounds for the problem.
Back to Top
Q: I am having a problem using your ActiveX Controls in .NET. Are there any issues I should know about?
A: The following error has been experienced by some customers:

"The referenced component could not be found. Invalid Primitive Type: System.Reflection.Missing. Only CLS compliant primitive types can be used. Consider using CodeObjectCreateExpression."

SP3 for Framework 1.0 and SP1 for Framework 1.1 broke compatibility with some ActiveX controls. You need to download a hotfix from Microsoft.

Anyone you distribute your app to will also have to run this hotfix until Microsoft releases SP4 for Framework 1.0 and SP2 for Framework 1.1


Back to Top
Q: I have a web page that embeds your ActiveX control that works on my development machine. On another machine, a red 'X' appears or the controls shows the Trial Message.
A: The problem is that a runtime license needs to be provided for the control. Resolution: Get LPK_TOOL.EXE from Microsoft. You can find it in their Cabinet Development kit. It is also on one of the CDs that comes with Visual Studio. Use the LPK_TOOL to create an .lpk file for YOUR control. We can't stress YOUR control enough. In other words, let's say that you have a control called MyControl that contains several Dart controls. When choosing the control in the LPK_TOOL listbox, choose MyControl, NOT the Dart Controls. Again, we can't stress this part enough as it is ALWAYS the part that is missed. Add the following to your document BEFORE any other objects are declared. Make sure LPKNAME.LPK is the name of YOUR lpk: <OBJECT CLASSID=clsid:5220cb21-c88d-11cf-b347-00aa00a28331> <PARAM NAME='LPKPath' VALUE='LPKNAME.LPK'>
Back to Top
Q: I want to inspect the header of a remote file, and only download it if contains specific content. How would I deal with this?
A: You can start a download using a stream, and inspect the stream as you read it. If it doesn’t meet your criteria, the transfer can be cleanly aborted without spooling any data to disk. If you choose to process the file, continue reading the stream until empty.
Back to Top
Q: I want to use your control in a non-VB environment (e.g. Sybase or Borland) AND create it dynamically. It works on my development machine, but elsewhere it throws a license error.
A: PowerTCP uses what is known as ClassFactory2 licensing. This is a system developed by Microsoft as part of the COM architecture. All of the major development environments that we use support this type of licensing when a control is placed on a form, however, only VB or VBA type environments support it when the control is 'created' without a form. By created, this means Dimming as New, not CreateObject. Of the other environments, we currently only provide direct support only for dynamic usage in Visual C++. See the component wrappers for the code needed to instantiate an object with a license. ( Example: ITcp.h and ITcp.cpp included with the sample projects ) If you absolutely HAVE to use our products in a project without a form, you will need to get direction from the company that makes the environment ( Example: Borland, Sybase ) on how to use COM objects that require ClassFactory2 licensing. If contacting them is not an option or is too costly, we may be able to assist you if you have one of the higher level support options or purchase incident support.
Back to Top
Q: I work in non-Microsoft environments. Can your product help me?
A: Absolutely! We ship samples written in Delphi, PowerBuilder and PowerBuilder (in addition to Visual Basic 6, Visual Basic 7 (.NET), C++, and ASP). In addition, we have customers using our products in FoxPro, Cold Fusion, Java Script, and other “COM-enabled” environments.
Back to Top
Q: I’m behind a firewall or proxy. Can I use your product to communicate through it?
A: When used without SSL encryption, there is no problem navigating firewalls or proxies. If you are using SSL encryption, only SOCKS proxies will properly allow navigation in secure mode.
Back to Top
Q: I’m new to Internet Protocols, and all I know is that I have to transfer a file using FTP. Am I in the right place?
A: Yes you are. PowerTCP allows you to do everything supported by the FTP protocol, in almost any manner you choose. You can buy with confidence from the market leader and our support staff is ready to answer any questions you may have!
Back to Top
Q: If a listing is not recognized as a DOS or UNIX listing, can I still use your control?
A: Sure. If we can't parse the listing, the text is still available for you to parse in your application.
Back to Top
Q: In Powerbuilder, the hourglass cursor does not persist when the Dart control is busy. How can I keep the hourglass?
A: Unlike other environments, the interface is automatically disabled when the cursor changes to an hourglass in Powerbuilder.

Including the code below will allow the hourglass to persist, but it will not automatically disable the interface. To produce the usual hourglass behavior, the interface must be explicitely disabled and enabled by the user.

//In the external global function declarations
FUNCTION ulong SetCapture(ulong a) LIBRARY "user32.dll"
FUNCTION boolean ReleaseCapture()
LIBRARY "user32.dll"

//In the script
ulong ll_handle, ll_rc
ll_handle = Handle(this)
ll_rc = SetCapture(ll_handle)
SetPointer(hourglass!)

//after done
ReleaseCapture()

Back to Top
Q: Is the free trial a 'full version'?
A: Yes. Your trial download is identical to the purchased product. The only difference is the trial download will only work for 30 days (in the case of ActiveX products) or will work for 7 days between each rebuild (for .NET products).
Back to Top
Q: Is this product interoperable with the .NET framework?
A: .NET COM interop is used to utilize this control within .NET, and a Visual Basic 7 sample is provided.
Back to Top
Q: My server responds to proprietary FTP commands that are not part of the RFC. How do you deal with that?
A: The Command() method can be used to send any arbitrary command to your FTP server.
Back to Top
Q: There are numerous FTP controls on the market. How is yours different?
A: PowerTCP supports BOTH synchronous and asynchronous operation, giving you the flexibility to change your application’s design without buying another product. In addition, PowerTCP implements the FTP protocol from scratch, in contrast to other vendors that only provide a thin wrapper to WININET.DLL functionality (that has known interoperability issues and provides more limited functionality for demanding applications). Finally, Dart focuses on product support, with a superior value proposition for professional developers.
Back to Top
Q: Why am I getting a Type Mismatch error in VBScript?
A: When using our controls in VBScript, you must specify optional parameters to prevent Type Mismatch errors.
For example, to zip a file with the FileStore, you need to create a SpanSettings instance:

Dim span
Set span = CreateObject("Dart.SpanSettings.1")
...
Zip1.FileStore.Zip("c:\Test\test.zip", span)

Back to Top
Q: I don’t know the first thing about SSL. Can you give me an overview that relates it to your product?
A: Basically, once a TCP connection is established, the server identifies itself with a special digital certificate that identifies it as “trustedE Optionally, the server may then require the client to identify itself with a digital certificate. If the respective certificates “pass musterE then all data is encrypted/decrypted using public key technology. PowerTCP makes all this as transparent as possible, while giving you the greatest control over accepting/rejecting certificates.
Back to Top
Q: I exported a certificate from my UNIX operating system to use with your product in SSL mode, but it doesn't seem to work.
A: Our implementation requires that a certificate be properly imported into a valid Microsoft Certificate Store. If you are importing a certificate that was created from a non-MS source (such as OpenSSL), please be sure that you export the certificate properly before attempting to import it into an MS Cert store. Check the docs for whatever SSL system you are using for this info. Also, make sure that when you export your certificate, regardless of your SSL library, that it includes the private key. A certificate that is exported without a private key can not be used as a valid certificate when imported into the Microsoft Certificate Store.
Back to Top
Q: I’m new to secure communications, and I’m not sure what I need. What should be my first step?
A: Dart has put all our Secure Socket Layer (SSL) related controls into the PowerTCP SSL Tool, so you are in the right place. Our knowledgeable pre-sales support staff will help point you towards the best solution for your project. Call us about your specific application, and we will help you determine the best approach to meet your design goals.
Back to Top
Q: Can I use an ActiveX control in a .NET Windows Service?
A:

Yes, with reservations, particularly for server-side controls. Dart ActiveX controls require a message pump to process events. Unfortunately, .NET services do not implement a message pump. Therefore, server-side controls (Server, WebServer, FtpServer, etc) that require events to function cannot be used effectively in .NET services.

It may be possible for the user to implement a message pump on the application level in a .NET service.  We encourage our users to post working solutions on our forum.

Also, licensing of ActiveX controls in .NET requires the presence of the development license in the registry of the machine running the service.  The registry location of the license is:
HKEY_LOCAL_MACHINE / SOFTWARE / Dart / PowerTCP / License
This requirement is the same as for ASP deployment, and is further outlined on the Distribution page of the help file, under the heading "Distribution Under IIS."

As always, Dart controls can be used in a COM environment to develop Windows services (for example, with the PowerTCP Service control).

 


Back to Top
Q: Can I use the ActiveX controls in a scripting language such as VBScript?
A:

Yes, in most environments the ActiveX controls can be used in a scripting engine such as VBScript.

 

However, while the controls will work on 64 bit machines in compiled environments such as VB6 and VC++, they are limited to 32 bit Operating Systems in scripting environments.


Back to Top

Related Content: