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Q130835: Class Browser: How to Save Data to a File

Article: Q130835
Product(s): Microsoft FoxPro
Version(s): 3.0
Operating System(s): 
Keyword(s): kbvfp
Last Modified: 15-FEB-2000

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, Professional Edition, version 3.0 
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SUMMARY
=======

The Class Browser is a tool provided with the Professional Edition of Visual
FoxPro. It allows you to browse and perform diverse tasks on classes stored in
visual class libraries (.VCX files). In particular, you can use the Class
Browser to save the source code for class definitions to a program file.

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

Saving the source code of a visual class definition to a program file might be
useful when debugging an application. The EXPORTCLASS() method of the Class
Browser generates and displays the definition source code of a selected class.

You can save this information to a program file (.PRG). The EXPORTCLASS method is
called when you choose the View Class Code button in the Class Browser. You can
also call it interactively, or customize the Class Browser to prompt a Save As
dialog to save information to a file. These two methods are described below.

NOTE: Attempting to run the .prg file may create an error. Not all of the code
exported to the .prg file is directly supported by the Visual FoxPro language.
The ExportClass method is not intended to create program code for a class
definition. Its purpose is to allow you to view how the class is defined. In
particular, the type of objects that will not work when the code from the Class
Browser is exported to a program file are container type objects that contain
other objects. For example, if you create a grid and change the ColumnCount
property to something other than -1, and use the Class Browser to export the
code to a .prg file, you will receive an "Syntax Error" message when trying to
run the .prg file. This happens because there is a set number of columns,
headers, and text boxes assigned to the grid. If the ColumnCount is left at -1,
the grid will properly populate itself from the table dynamically. The same
thing happens with a PageFrame. If the code for the PageFrame is copied to a
.prg file and there are no objects on the PageFrame, then the code works
properly. Adding an object to the PageFrame and then copying the code to a .prg
file causes the "Syntax Error" message.

Method One: Use the ExportClass Method Interactively
----------------------------------------------------

1. Choose Class Browser from the Tools menu to start the Class Browser.

2. Select the visual class library, and select the class.

3. From the Command window, type:

     lcCode=_oBrowser.ExportClass()

4. To save the information to a file, use this code:

        SET PRINT TO TESTCLASS.PRG
        SET PRINT ON
        ?lcCode
        SET PRINT TO
        SET PRINT OFF

Method Two: Create an Add-in to Customize the View Class Definition Button
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WARNING: If you use the following information to customize the Class Browser,
your customized Class Browser may no longer be supported by Microsoft.

You can create an add-in that will extend the functionality of the View Class
Definition button. To execute this add-in, right-click the View Class definition
button. The code is displayed in a window, and the SaveAs dialog is displayed to
save the code to a program file. Sample code for the add-in is included below.

For more information about the ExportClass and the Addin methods of the Class
Browser, please search for "Class Browser Methods" in the Help menu.

How to Install or Remove the Add-In
-----------------------------------

To install the add-in:

1. Start the Class Browser.

2. Type the following code in the Command window:

        _oBrowser.AddIn('Export SaveAs','exportsv','cmdExport.RightClick')

Exportsv is the name of the program to execute when the RightClick event is
triggered.

To remove the add-in, type the following code in the Command window:

     _oBrowser.AddIn('Export SaveAs',.NULL.)

Sample Code for the Add-In
--------------------------

     *  EXPORTSV.PRG
     *  After installing the add-in, right-click the mouse on the View Class
     *  Definition button.
     *
     *  You can also link this code to the Click event handler rather than
     *  the Right-click event handler. Change the install method
     *  parameter passed to AddIn() to 'cmdExport.Click' and then add
     *  oSource.lNoDefault=.T. to the program below.

     LPARAMETERS oSource
     LOCAL lcCode,lcFileName,lnLastSelect

     *-- Execute export class method.
     *-- Note:  If you don't want the code to be displayed in the window,
     *          don't pass the .T. parameter.
     lcCode=oSource.ExportClass(.T.)

     IF EMPTY(lcCode)        &&& No code was generated
        RETURN
     ENDIF

     *-- Get file to save the generated class code to.
     lcFileName=GETFILE('prg')
     IF EMPTY(lcFileName)    &&& No file was selected or entered.
             RETURN
     ENDIF

     *-- Create a cursor to save the generated string to a file.
     lnLastSelect=SELECT()
     IF USED('tempexport')
          USE IN tempexport
     ENDIF
     CREATE CURSOR tempexport (mCode M)
     INSERT INTO tempexport (mCode) ;
                  VALUES (lcCode)
     COPY MEMO mCode TO (lcFileName)
     IF USED('tempexport')
          USE IN tempexport
     ENDIF
     SELECT (lnLastSelect)
     RETURN

Additional query words:

======================================================================
Keywords          : kbvfp 
Technology        : kbVFPsearch kbAudDeveloper kbVFP300
Version           : :3.0
Issue type        : kbhowto

=============================================================================

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