MORE INFORMATION
_SCREEN and activeControl Property
In previous versions of FoxPro, you may have used the FoxPro system
variable _CUROBJ to refer to the object that currently had the focus.
Although the _CUROBJ variable has been retained for backward compatibility,
Microsoft recommends that you now refer to an object or control on a form
by using the _SCREEN reference and activeControl property. To return the
name of the control that has the focus use this code:
_SCREEN.activeform.activecontrol.name
thisform.activecontrol.name
-or- (if the form is part of a formset)
thisformset.thisform.activecontrol.name
To return the name of the current control, use this code:
CurControl=_SCREEN.activeform.activecontrol.name or
CurControl=thisform.activecontrol.name
-or- (if the form is part of a formset)
thisformset.CurControl=thisform.activecontrol.name
To set the caption of the current control, use this code:
_SCREEN.activeform.activecontrol.caption="my caption"
thisform.activecontrol.caption="my caption"
-or- (if the form is part of a formset)
thisformset.thisform.activecontrol.caption="my caption"
To move the cursor to a control, use this code:
_screen.activeform.<controlname>.setfocus
thisform.<controlname>.setfocus
-or- (if the form is part of a formset)
thisformset.thisform.<controlname>.setfocus
NOTE: <controlname> is the name of the control you wish to become active.
/N Parameter on the RUN Command
The RUN command is available on the Windows platform only. The RUN command
in FoxPro for Windows has a /N parameter that allows you to launch a
Windows-based application. In fact, FoxPro for Windows introduced the /N
option for executing windows-based applications from FoxPro. This
functionality is retained in Visual FoxPro. The following command launches
Word for Windows, and opens the readme document.
RUN /N <drive><path>WINWORD.EXE README.DOC
The Microsoft Windows Control Panel contains many utilities that you can
use in your applications. You can also call these utilities using the RUN
command:
RUN /N CONTROL COLOR
RUN /N CONTROL PRINTERS
RUN /N CONTROL DESKTOP
You can include an optional numeric value immediately after /N to specify
how the Windows-based application is opened. Do not include any spaces
between /N and the numeric value. The following table lists the numeric
value you can include and describes the state of the Windows-based
application when opened.
Value Application attributes
------------------------------------------------
1 Active and normal size
2 Active and minimized
3 Active and maximized
4 Inactive and normal (won't work with Windows 95)
7 Inactive and minimized
Drives and Directories
Several FoxPro functions can be used to obtain information about drives and
directories. Compare the returned values after issuing the command SET
DEFAULT TO C:\VFP.
Drive:
SYS(5) returns C:
SET('DEFAULT') returns C:
Directories:
CURDIR()returns \VFP\
SYS(2003) returns \VFP
FULL(SET('DEFA')) returns C:\VFP\
You can also use the ADIR() function to see if a specific directory exists.
The following example returns 0 only if the path name does not exist.
Remember that the path to a network server may not exist if the network
connection is broken.
? ADIR(temparr,'C:\VFP\*.*','D')
returns 0
USE Command
You can run the USE IN 0 command to open a table or .dbf file in the first
available work area. This command does not select that work area in which
it opened the table or .dbf file. You must use the SELECT command to do
this. You can issue the command USE IN <alias> to close a table or .dbf
file without selecting its work area.
A new SHARED clause for the USE command allows you to open a table or .dbf
file for shared use without using the SET EXCLUSIVE command. For more
information about the USE command, refer to the USE topic in the Help file.
Cross-Tab Output to Spreadsheets
Genxtab has been replaced by the Fpxtab program and is called from the code
created by the Query Wizard. After running the Query Wizard select the
Cross-Tab Wizard from the first screen, and follow the instructions to
create a table that can then be exported or copied to spreadsheets.
Custom Messages
You can display custom messages in the FoxPro status bar. To do this, type
the following in the Command window:
SET TALK OFF
SET MESSAGE TO <expC>
Where <expC> is the message. (You can pass a null string to display
nothing.) SET MESSAGE TO without a parameter will restore the status bar to
its normal functionality.
Preprocessor Directives
Do not use _WINDOWS, _DOS, _MAC, or _UNIX with preprocessor directives
(that is, #IF...#ENDIF). These are designed to be runtime variables. For
example the following will NOT work:
#define _DOS .t.
#define _WINDOWS .f.
* For code compiled in MS-DOS, the following would not work:
DO CASE
CASE _DOS
? "Running in MS-DOS"
CASE _WINDOWS
? "Running in Windows"
ENDCASE
This code would not work because _DOS would be changed to .T. and _WINDOWS
would be changed to .F. so that the code could never work properly again.
Instead use the following:
#if "Win" $ VERS()
#define WINDOWS_CODE .t.
#elif "Mac" $ VERS()
#define MAC_CODE .t.
#elif "Unix" $ VERS()
#define UNIX_CODE .t.
#else
#define DOS_CODE .t.
#ENDIF
#if WINDOWS_CODE
? "Compiled under WINDOWS"
#elif DOS_CODE
? "Compiled under MS-DOS"
#ENDIF
Preprocessor Substitution in Text Strings
In FoxPro 2.6, #define prevented preprocessor substitution in text strings.
This has been remedied in Visual FoxPro. The following code will work as
expected returning the text 'test' from the function call. In FoxPro 2.x
this would have resulted in a 'NOSUB not found error' message. This is
because of the way the '[]' characters were evaluated.
#DEFINE nosub 1
DECLARE an_array(3)
an_array(nosub)='test'
? afunc[an_array[nosub]]
FUNCTION afunc
PARAMETER x
RETURN x
Development Tools
The Foxtools.fll file, which is located in your FoxPro for Windows root
directory, contains a variety of functions you can use to enhance your
applications. Many of these functions provide access to API routines and
Microsoft Windows functions. You can view these by using the DISPLAY STATUS
command (after you use SET LIBRARY TO foxtools). Use of the window API
routines is also supported through the use of the DECLARE statement.