Improve your SAS applications by using functionality built in the MS Windows API, such as accessing external DLLs, OCXs and OLE servers.

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1 Improve your SAS applications by using functionality built in the MS Windows API, such as accessing external DLLs, OCXs and OLE servers. Introduction Johan Jerresand, Niklas Data AB The purpose of this paper is to show how to use a new way of thinking when developing applications in the MS Windows environment to make it easier for the user to use the application when it s ready. The main problem is that people developing systems have been focusing on how their application should work on its own data. Instead system developers should try to take advantage of things that already have been developed by other vendors and integrate this functionality with the one they have to implement themselves. To be able to do this system developers need a standard. In the Windows environment we now have such a standard to use when developing our applications. This standard is called OLE (Object Linking and Embedding) and with this standard we can integrate different kind of applications following the OLE standard very closely. Almost all applications developed for MS Windows have a set of DLLs (Dynamic Link Libraries) encapsulating most of the functionality used in the application. By giving information how this functionality can be accessed, all developers can use this in applications that are to be developed. This will most likely shorten the process of developing new applications. In SAS version 6.11 you can access functionality stored in such external DLL files if you are familiar with the parameters used when calling for this functionality. OCXs (OLE Custom extensions) is a special type of a Dynamic Link Libraries that have a user interface connected. In SAS version 6.11 you can use OCXs when developing AF applications. A reason for using OCXs in your AF application can be that you re not satisfied with the user interface for a specific item in SAS AF or that you want to develop a routine in another software and then use it in your AF application.

2 Niklas Data Group The Niklas Data Group is a group of SAS consulting companies, owned by the founders and management. Since the start in 1987, our vision has been to be the preferred provider of solutions based on the SAS System. In 1994 we became a certified SAS Quality Partner, as the first consulting company in Scandinavia. By autumn 1995 we were one of the charter members of SAS Institute's initiative "Rapid Warehousing Program". Our head office is situated in Amsterdam, the Netherlands. Currently we have subsidiaries in Sweden, Norway and Finland. Our business strategy and competitive edge is that we only focus on SAS. The Niklas Data Group employs over 75 consultants specialised in developing SAS applications for a multitude of companies, corporations and organizations. DLL - Dynamic Link Library What is a Dynamic Link Library The entire Windows environment and applications installed in the system are based on a large set of Dynamic Link Libraries. A DLL is a special type of executable file that are linked to an application in run-time when functionality stored in the DLL is needed by the application. By distributing functionality to a number of small packages we don t have to load a big executable file at once when starting an application. Instead we can link this functionality when we need it and then swap it out of memory when we don t need it. SAS Dynamic Link Libraries The SAS system is under the Windows environment built on a large set of different DLL files containing the procedures needed to do our analysis or the functionality needed building an AF application. Each module operating in the SAS system has its own set of DLL files with the corresponding functionality stored in a module dependent directory. External Dynamic Link Libraries In SAS version 6.11 it s also possible to access Dynamic Link Libraries not contained in the SAS system. This gives us a whole new world of predefined and tested functionality from other vendors available when developing our systems. The best is probably that we get access to functionality built in the Windows operating system. If you have access to documentation of the functionality built in the Windows DLL files you can put this into your datastep programs, IML programs or into your SCL code to get easy access to specific system information for example. Earlier you had to access this information by

3 giving DOS commands, through the x command and then handle the output of the command. Communication with external DLL files is an operation on a low level. This means you have to know the exact way of how communication with the DLL file should be handled before you try to use it in a production system. When invoking an external DLL file program, control is lost by SAS and transferred to the DLL routine. Sending the wrong parameters to the external DLL file could very easy end with a General Protection Fault, making the operating system unstable. But used in the appropriate way it can help you a lot in the program developing process. Lots of different programming languages can be used to store functionality in Dynamic Link Libraries. How to access external Dynamic Link Libraries from within SAS A routine stored in an external DLL file is invoked from within the SAS by module call routines and module functions. Steps to take when accessing external DLL files 1. Create a text file that describes the name of the DLL routine with the routine needed, the arguments required and values returned. 2. Create a filename SASCBTBL referring to the text file created in step Invoke the DLL routine by using a call routine or function call (MODULExy). OLE - Object Linking and Embedding Why has a standard like OLE been defined? - To make it easy for application developers to integrate different kind of applications. - Computers aren t as easy to use as they should be. - Complexity with computers and information in networks isn t hidden sufficiently from the ordinary user. A way to reach these goals is to use OLE. This makes it possible for you to solve your problems using an object oriented application approach.

4 Data types OLE associates two major types of data with an object: presentation data and native data. An object's presentation data is information needed to present the object on a display device, while its native data is all the information needed for an application to edit the object. Linking vs. Embedding In OLE users can either link or embed objects into their documents. When linking data only the object's presentation data and a reference to its native data are placed in the document. The actual native data associated with the object exists in some other location such as in a file on disk. To the user, a linked object acts as if it was contained within the document. When embedding objects both presentation data and native data physically resides within the document. Embedding objects makes the document larger but it s easy to move to another computer for example. An advantage with linked objects is that they can serve more than one application at a time without using any extra disk space. A disadvantage with linked objects is that you can t move them to another computer if you don t move the locally stored data as well. Container - Compound documents Everything that contains objects is called a container. Containers are typically compound documents - documents consisting of objects from multiple source applications. When adding an OLE object into your SAS AF application the frame becomes a Container. Note. SAS is a 32 bit container and can therefore only hold 32 bit OLE objects. Functionality built in OLE 2 - Visual editing In OLE 1.0 activating an object within a document is achieved by doubleclicking the object, and then transferring program control to a different application window, to be able to edit the object. In OLE 2 the user can interact with an object in the compound document by double-clicking the object and then work with the object in-place without having to enter a new application window. This functionality hides, for the user, the actual server application used to modify the object selected.

5 When double-clicking an object in the compound document, all menus, toolbars, palettes and other controls necessary to interact with the object in the client application is substituted with the ones defined in the server application. You can say that the server application is taking control of the document window in the client application. When focus returns to the container application the original menus and controls are restored. Embedded objects can be both activated for displaying and editing in-place of the compound document, a linked object can only be displayed and not edited in-place. - Nested objects In OLE 2.0 links that refer to objects or even parts of objects that are embedded in other objects are supported. These features are powerful because they give users freedom to manipulate objects in limitless combinations and work with compound documents more productively. - Storage independent links OLE 2 supports an extended linking mechanism giving greater flexibility when linking objects. In this new linking mechanism links to objects are independent of the underlying storage system. Previously links could only be established between objects that where stored within the computer's file system. Links can now be updated between objects within the same or different documents, without requiring that the objects exist on disk. - Adaptable links In OLE 2 links are maintained if both source object and linked object are copied simultaneously to the same destination. This wasn t the case in OLE 1. - OLE Automation With OLE 2, programmers can define a set of operations and make them accessible to other applications. These operations can have argument lists, much like an ordinary function call in a programming language. This makes it possible for us to exchange data between SAS and other applications, with for example MS Excel by using Visual Basic commands and with MS Word by using Word Basic commands, without any interaction by the user - Object conversion OLE 2 supports a method for converting objects from one application to another. If for example an object including a spreadsheet created by one

6 application are used in a system with another spreadsheet application, OLE 2 will convert the spreadsheet in the object to match the spreadsheet application used in this system. - Version management Information about the version of server application that created the object is in OLE 2 stored with the object. This makes it possible for systems using newer versions of the server software to convert the OLE objects that where created by an older version of the software. - Drag and Drop Earlier the clipboard area was used when copying data between different applications. In OLE 2 support for drag and drop gives us the ability to skip the step of copying data to the clipboard, and instead drag data from one OLE object and then drop it on another OLE object. The following types of drag and dropping is supported - Inter-window dragging: Objects can be dragged from one application window and dropped into another application window. - Inter-Object dragging: Objects nested into within each other can be dragged to another window or another container object. - Dropping over icons: Object can be dragged to for example system resource icons like printmanager. To be able to use drag and drop between OLE objects in your Frame application the object has to be registered with a valid drag and drop representation. The representation used with OLE objects is SAS_DND_OLEOBJ. Document oriented applications As user of an application you aren t interested in, the application used to solve your problem but to solve the problem. If you for example are creating a document in a word processor and have a picture inserted in the document that you want to edit, you don t want to leave the application and enter another application that has the ability to edit the picture inserted in your document. What you should try to do is to hide this for the user of the application so he or she can concentrate on the work that has to be done and not on what application to use on this specific object. That new approach to application development is called document oriented. The purpose for this new approach is to let the document be in focus and not the applications used. The user should stay in the same client area

7 independent of what application is used to modify the document. This gives us a client/server environment where, in our example, the word processor is both client and server and other applications are started as server applications to handle modifications on specific objects linked or embedded to the compound document used by the user. Client - Server Compound documents use different server applications to handle different kinds of objects in the document. There are two types of server applications, mini-servers and full servers. Mini - Full servers A mini server can be launched only by a client and not run as a stand-alone application. A mini-server does not store documents as their own files on disk, instead, it reads its documents from and writes them to items in client documents. By not being able to handle files stored in files on disk this type of server can only handle embedded and not linked objects. A full server is a stand-alone application, it can either be run by itself or be launched by a client application. A full server does support storing document on disk as their own files. A server of this type can support embedding or both embedding and linking. SDI - MDI servers There is another dimension of the mini- and full server issue and that is, if the server is a SDI (Single Document Interface) or MDI (Multiple Document Interface) application. SDI applications can handle one document at the time in the client area of the application. The MDI application has the ability to handle more than one document at a time in the client area. A server application must be able to handle more than one client simultaneously, in case more than one client wants to edit an embedded or linked object. If the server is an SDI application it must be possible with multiple instances of the server to be running simultaneously. This will allow a separate instance of the application to handle each clients requests. If the server is a MDI application it can create a new MDI child window for each new client. By using SDI servers we let a new instance serve each new client and when using MDI servers a single instance of the server application will handle all clients requests.

8 OCX - OLE Custom extension What is an OCX An OCX is an OLE 2 compound object with support for visual editing. The OCX has more functionality than an ordinary OLE object, such as the ability to generate events. An OCX has it s own interface to expose it s properties. This functionality can be accessed from within SAS by using the controls graphical interface or by using SCL code. Implementing an OCX may take a long time but the advantage is that when developed and tested it can be used by most applications running in the Windows environment. When writing an OCX an OLE control file has to be produced. This control file is a DLL file that defines the functionality for one or more controls. OCXs you develop on your own can freely be distributed to other users and developers. How to access information from an OCX in SAS The OCXs properties are accessed and controlled by the SCL methods _get_property_ and _set_property_. You also need to know what kind of properties that are available and what parameters they need. Interaction between SAS and the OCX is controlled by the methods _do_ and _compute_. The _do_ method works as a procedure not returning any information and the _compute_ method is more like a function call giving some information back. If using some functionality in the OCXs frequently you can subclass them and write your own SCL methods to easier get access to the functionality. Registration Before an OCX can be used from within SAS you have to register it with Windows. The OCX will not be available until this registration is done. This is some of the information loaded into the Windows registration database when registering an OCX. - The text name of the control. - The class name of the control. - The path of the controls DLL file. - Whether the control is insertable or not.

Conclusion By using SAS as an OLE container application you let the user get access to the functionality prebuilt in the SAS system and the functionality defined in for example MS Excel and MS Word

Using OCXs gives you a large amount of new predefined and tested functionality Graphical User Interface objects.

9 Conclusion By using SAS as an OLE container application you let the user get access to the functionality prebuilt in the SAS system and the functionality defined in for example MS Excel and MS Word without having to leave the client window of the application. The document oriented way of system development. Using OCXs gives you a large amount of new predefined and tested functionality Graphical User Interface objects. Using the ability to access external DLL files gives you a great opportunity to let your SAS application merge into the Windows operating system. This by calling functions predefined in the Windows Application Programming Interface. By Johan Jerresand Niklas Data AB Fiskhamnsgatan GÖTEBORG SWEDEN Phone SAS is a registred trademark of SAS Institute Inc., Cary, NC, USA.

Using OLE in SAS/AF Software

187 CHAPTER 9 Using OLE in SAS/AF Software About OLE 188 SAS/AF Catalog Compatibility 188 Inserting an OLE Object in a FRAME Entry 188 Inserting an OLE Object 189 Pasting an OLE Object from the Clipboard