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The Catalyst Internet Mail Control license permits the use of the ActiveX control to build application software and redistribute that software to end-users. There are no restrictions on the number of products in which the controls may be used. However, if the product has been installed with an evaluation license, any software created using its components cannot be redistributed to another system until a licensed copy of the toolkit has been purchased. System RequirementsThe Catalyst Internet Mail control is designed for the Windows platform, and is supported on Windows Vista, Windows Server 2003, Windows XP and Windows 2000. It is recommended that all platforms have the latest available version of Internet Explorer installed, along with all service packs and critical updates.
Earlier versions of the Windows operating system, including Windows 95, Windows 98, Windows Me, Windows NT 3.51 and Windows NT 4.0 are no longer supported by Microsoft. Using Catalyst Internet Mail control on an unsupported platform may require that the user install additional system components such as the Microsoft Layer for Unicode and the latest available version of Internet Explorer. Control RedistributionFor those applications created using the Catalyst Internet Mail control, it must be distributed along with the application and the control must be registered by the installation program. The process of registration means that specific entries must be created in the system registry which provide information about the control such as the location of the OCX file. Fortunately, ActiveX controls are self-registering, which means that the control has the ability to create or update those registry entries itself. To take advantage of this, the installation program must be capable of loading the control and calling those functions inside the control which update the registry. Most modern installation tools are capable of registering ActiveX controls. For in-house setup programs, refer to the technical article on ActiveX Control Registration on the Microsoft Developers Network CD. It is possible to register ActiveX controls manually without the use of an installation program. This may be desirable in those situations where an application is being deployed internally or the developer does not want to create a setup program for a limited distribution. The tool used to manually register a control is named RegSvr32 and can be obtained from a number of places including the Visual Basic or Visual C++ CD-ROM. This utility accepts a command line argument which specifies the name of the control to register. For example, the following command would register the control:
A message box would be displayed indicating that the control was registered successfully. To prevent the message box from being displayed, use the /S option which tells the utility to function silently. If an error is reported, typically the reason is that a required system DLL is missing or out of date.
Version InformationThe Catalyst Internet Mail control has embedded information which provides version information to an installation utility. This information, called the version resource, specifies the control's version number among other things. If you are using a third-party or in-house installation program, it is extremely important that the program knows how to use this information. For example, if you are deploying an application which uses the control, the setup program must determine if it has already been installed on the target system. If it has, it must compare the version resource information in the two files. It should only overwrite the file if the version that you have included with your application is later than the one installed on the system. An installation program which overwrites the file without checking the version number may cause other programs to fail unexpectedly on the end-user's system, which is obviously not desirable. Installation DirectoryThe Catalyst Internet Mail control should typically be installed in the \Windows\System32 directory on the local machine. Some developers may prefer to install the control along with their application in a private directory. It is not recommended that developers take this approach unless COM redirection or registration-free activation is used because the full pathname of the control file is stored in the system registry when it's registered. If multiple applications install the same control in different directories, the actual control that will be used is the one that was last registered. This means that it is possible that an application will load an earlier version of the control than it was built with, which may result in unexpected or fatal errors. COM redirection enables an application to isolate the controls that it uses, ensuring that the same version of the control which was used to build the application is loaded when the program is executed. To activate COM redirection, create an empty file named after the executable with a .local extension. For example, if the program is named MyProgram.exe then an empty file named MyProgram.exe.local should be created in the same directory as MyApp.exe. This binds the application to the local version of any controls which are installed in the same directory as the application. When an instance of the control is created, Windows will first search the application's directory, and then uses the standard search rules for locating the file. Note that COM redirection is not supported on Windows 95 or Windows 98. |
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Copyright © 2008 Catalyst Development Corporation. All rights reserved. |
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