DOCUMENT:Q265884 11-JAN-2001 [vbwin] TITLE :BUG: Optional Parameter with Default Value Null Causes Error 458 PRODUCT :Microsoft Visual Basic for Windows PROD/VER::5.0,6.0 OPER/SYS: KEYWORDS:kbActiveX kbVBp kbVBp500bug kbVBp600bug kbGrpDSVB kbDSupport ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Visual Basic Professional Edition for Windows, versions 5.0, 6.0 - Microsoft Visual Basic Enterprise Edition for Windows, versions 5.0, 6.0 ------------------------------------------------------------------------------- SYMPTOMS ======== If you declare an optional parameter of type Variant with the default value set to Null in your ActiveX Component Project (such as ActiveX DLL, ActiveX control (OCX), or ActiveX EXE), you receive the following error message (458) when you compile the project: Variable uses an Automation Type not supported in Visual Basic Visual Basic does not give you any details on which line of code causes the error. RESOLUTION ========== The workaround is to replace Null with the predefined constant vbNull. STATUS ====== Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. MORE INFORMATION ================ Steps to Reproduce Behavior --------------------------- 1. Start a new ActiveX DLL project in Visual Basic 6.0. Class1 is added by default. 2. Paste the following code into the code window of Class1: Option Explicit Public Sub Method1(Optional ByVal x As Variant = Null) ' End Sub 3. On the File menu, select Save Project. 4. On the File menu, select Make Project1.dll, and note that you receive the previous error message immediately. 5. Change Null to vbNull in the preceding code, repeat steps 3 and 4, and note that the project compiles without error. Additional query words: Error 458 compile-time ====================================================================== Keywords : kbActiveX kbVBp kbVBp500bug kbVBp600bug kbGrpDSVB kbDSupport Technology : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVB600Search kbVBA500 kbVBA600 kbVB500 kbVB600 Version : :5.0,6.0 Issue type : kbbug Solution Type : kbpending ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2001.