Q255279: HOWTO: Create a COM DLL with Visual FoxPro that Prints Screen Im

Article: Q255279
Product(s): Microsoft FoxPro
Version(s): WINDOWS:6.0
Operating System(s): 
Keyword(s): kbprint kbCOMt kbPrinting kbvfp600 kbGrpDSFox kbDSupport kbCodeSnippet
Last Modified: 11-SEP-2001

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, version 6.0 
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SUMMARY
=======

This article demonstrates, by example, the general ease with which Component
Object Model (COM) DLLs can be created within Microsoft Visual FoxPro 6.0. The
program code contained in this article enables the user to create a useful
example of a simple COM DLL.

MORE INFORMATION
================

In order for the example to be put to use, the host computer must have a
properly installed copy of Microsoft Office for Windows 95 (or higher). The COM
DLL offers the following functionalities:

- It captures the screen image of the open and active window.

- An OLE instance of Microsoft Word is created for the purpose of printing the
  captured screen image.

- The captured screen image is pasted into a Microsoft Word document.

- The Microsoft Word Document is printed to the computer's default printer.

To create the COM DLL described in this example, perform the following steps:

1. Within Microsoft Visual FoxPro 6.0, create a new project called "olepscrn"
  (without the quotation marks).

2. Add a new program to the olepscrn project, and input the following code:

  *!* Beginning of program code example:
  DEFINE CLASS p_screen AS CUSTOM OLEPUBLIC
      Name = "p_screen"
      ScreenPrinted = .F.
      oWordObj = ""
      PROCEDURE ScreenCapture
          This.ReleaseWord()
          This.ScreenPrinted = .T.
          DECLARE INTEGER keybd_event IN Win32API ;
              INTEGER, INTEGER, INTEGER, INTEGER
          VK_SNAPSHOT = 44
          =keybd_event(VK_SNAPSHOT, 1, 0, 0)
          This.oWordObj=CREATEOBJECT("Word.Application")
          This.oWordObj.Documents.Add
          This.oWordObj.ActiveDocument.PageSetup.Orientation = 1
          WITH This.oWordObj.WordBasic
              .EditPaste
              .FilePrint
              .FileClose(2)
          ENDWITH
          RELEASE keybd_event, vk_snapshot
      ENDPROC
      PROCEDURE ReleaseWord
          IF This.ScreenPrinted
              This.oWordObj.Quit
              This.oWordObj = ""
              This.ScreenPrinted = .F.
          ENDIF
      ENDPROC
      PROCEDURE Destroy
          This.ReleaseWord()
      ENDPROC
  ENDDEFINE
  *!* End of program code example:

3. Save the program as "p_screen" (without the quotation marks).

4. On the Project Manager, select the Build button, and choose Single-threaded
  COM server (DLL) in Visual FoxPro 6.0 with SP3, or choose Build COM DLL in
  Visual FoxPro 6.0.

5. From the Command window, you can use the DLL by entering the following three
  commands:

  1. This command creates an object reference to the DLL and loads it into
     memory:

  oPScreen = CREATEOBJECT("olepscrn.p_screen")

  2. This command executes the Print Screen:

  oPScreen.ScreenCapture()

  3. This third and final command removes the DLL from memory. When the object
     is released, the instance of Microsoft Word that it created releases as
     well:

  RELEASE oPScreen

REFERENCES
==========

For additional information about programmatic screen capturing, click the
article number below to view the article in the Microsoft Knowledge Base:

  Q153003 How To Perform a Screen Capture Programmatically

For additional information about COM and VFP 6.0, click the article number below
to view the article in the Microsoft Knowledge Base:

  Q188709 Vfpcom.exe Using COM Language Enhancements in VFP 6.0

For more information about Creating Automation Servers, search for Extending
Applications, and then Adding OLE in Visual FoxPro Help.

Additional query words:

======================================================================
Keywords          : kbprint kbCOMt kbPrinting kbvfp600 kbGrpDSFox kbDSupport kbCodeSnippet 
Technology        : kbVFPsearch kbAudDeveloper kbVFP600
Version           : WINDOWS:6.0
Issue type        : kbhowto

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