Microsoft KB Archive/109059: Difference between revisions
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<span class="kbd userinput"> </span> | <span class="kbd userinput"> </span> | ||
<pre class="codesample"> SET LIBRARY TO SYS(2004)+ | <pre class="codesample"> SET LIBRARY TO SYS(2004)+"foxtools.fll" ADDITIVE | ||
* FindWindow() takes two parameters and returns the handle of the | * FindWindow() takes two parameters and returns the handle of the | ||
* window, HWND, if it was found. | * window, HWND, if it was found. | ||
GetWind = RegFn( | GetWind = RegFn("FindWindow", "CC", "I") | ||
*Set the first parameter of the call to getwind to 0, null. | *Set the first parameter of the call to getwind to 0, null. | ||
wclass=0 | wclass=0 | ||
winname= | winname="My Application" | ||
apphand=CallFn(GetWind,wclass ,winname) | apphand=CallFn(GetWind,wclass ,winname) | ||
*If the call was successful, stop processing. | *If the call was successful, stop processing. | ||
IF apphand | IF apphand<>0 | ||
WAIT WINDOW ; | WAIT WINDOW ; | ||
"You cannot start another instance of the window 'My Application'!" | |||
QUIT | QUIT | ||
ENDIF | ENDIF | ||
MODIFY WINDOW screen TITLE | MODIFY WINDOW screen TITLE "My Application" | ||
WAIT WINDOW ; | WAIT WINDOW ; | ||
"The first instance of the window 'My Application' is running." | |||
</pre> | </pre> | ||
| Line 89: | Line 89: | ||
== REFERENCES == | == REFERENCES == | ||
Microsoft Windows Software Development Kit, | Microsoft Windows Software Development Kit, "Programmer's Reference, Volume 2: Functions," page 309<br /> | ||
<br /> | <br /> | ||
Foxtools.hlp, located in the C:\Vfp\Tools | Foxtools.hlp, located in the C:\Vfp\Tools | ||
Latest revision as of 17:45, 20 July 2020
Article ID: 109059
Article Last Modified on 7/1/2004
APPLIES TO
- Microsoft Visual FoxPro 3.0 Standard Edition
- Microsoft Visual FoxPro 5.0 Standard Edition
This article was previously published under Q109059
SUMMARY
The program shown below demonstrates how to stop a second instance of the same FoxPro window from being started by using the Windows application programming interface (API) function FindWindow() to test if a given window name already exists. The FindWindow() function can be accessed by including FOXTOOLS.FLL, the library file that is supplied with FoxPro for Windows and documented in the Foxtools.hlp file.
NOTE: This method does not prevent multiple instances of FoxPro for Windows from starting.
MORE INFORMATION
NOTE: This works in Windows for Workgroups 3.00, Windows 95, and Windows NT.
Copy this code into a program file in FoxPro for windows. The first time you call the program, you will notice the main FoxPro window title change. The second time you run it, you will get the message that you cannot start another instance of the window.
NOTE: Set the window name after you check for its existence.
SET LIBRARY TO SYS(2004)+"foxtools.fll" ADDITIVE
* FindWindow() takes two parameters and returns the handle of the
* window, HWND, if it was found.
GetWind = RegFn("FindWindow", "CC", "I")
*Set the first parameter of the call to getwind to 0, null.
wclass=0
winname="My Application"
apphand=CallFn(GetWind,wclass ,winname)
*If the call was successful, stop processing.
IF apphand<>0
WAIT WINDOW ;
"You cannot start another instance of the window 'My Application'!"
QUIT
ENDIF
MODIFY WINDOW screen TITLE "My Application"
WAIT WINDOW ;
"The first instance of the window 'My Application' is running."
REFERENCES
Microsoft Windows Software Development Kit, "Programmer's Reference, Volume 2: Functions," page 309
Foxtools.hlp, located in the C:\Vfp\Tools
Additional query words: foxtools sdk fll api recursive recursion loaded twice
Keywords: kbhowto kbinterop kbcode KB109059
