Microsoft KB Archive/314849

= FIX: Parameters Passed as Empty Placeholders Default to NULL =

Article ID: 314849

Article Last Modified on 2/18/2002

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APPLIES TO


 * Microsoft Visual FoxPro 7.0 Professional Edition

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This article was previously published under Q314849



SYMPTOMS
When you pass a parameter as an empty placeholder to a COM object from Visual FoxPro (VFP) 7.0, the placeholder defaults to a value of NULL (rather than .F. as in earlier versions of VFP).



RESOLUTION
To resolve this problem, obtain the latest service pack for Visual FoxPro for Windows 7.0. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

316964 How to Obtain the Latest Visual FoxPro for Windows 7.0 Service Pack



STATUS
Microsoft has confirmed that this is a problem in Microsoft Visual FoxPro for Windows 7.0. This problem was first corrected in Visual FoxPro for Windows 7.0 Service Pack 1.



Steps to Reproduce Behavior
 Create a new folder on your hard disk. Copy the VFP 7.0 run-time files Vfp7r.dll and Vfp7enu.dll to the new folder. The version number of these files should be 9262.  Paste the following code in a new program (.prg) file and then save the file in the folder that you created in step 1: CD JUSTPATH(SYS(16)) LOCAL lcDLLStr AS STRING, ; loMyDll AS OBJECT CLEAR

TEXT TO lcDLLStr NOSHOW DEFINE CLASS SERVER AS SESSION OLEPUBLIC PROCEDURE SomeMethod(p1, p2, p3) RETURN p2   ENDPROC ENDDEFINE ENDTEXT

STRTOFILE(lcDLLStr, &quot;DLLMAIN.PRG&quot;, 0) CREATE PROJECT DLLMAIN NOWAIT _VFP.ACTIVEPROJECT.FILES.ADD(&quot;DLLMAIN.PRG&quot;) _VFP.ACTIVEPROJECT.BUILD('DLLMAIN',4) _VFP.ACTIVEPROJECT.CLOSE

loMyDll = CREATEOBJECT(&quot;DLLMAIN.SERVER&quot;) ? &quot;With params like loMyDll.SomeMethod(.F.,,.F.), P2 =&quot;,loMyDll.somemethod(.F.,,.F.) RELEASE loMyDll  Run the code.

The COM DLL that is created by the sample code returns NULL for the second parameter that it is passed. If you delete the run-time files from the folder (causing the COM DLL to use the VFP 7.0 SP1 versions of these files) and then rerun the sample code, the DLL will instead return .F. for the second parameter.

Additional query words: kbVFP700sp1fix

Keywords: kbbug kbfix kbcodesnippet KB314849

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