PRB: Error Saving a Form With ATL Control

• Microsoft Visual Basic Learning, Professional, and Enterprise Editions for Windows, versions 5.0, 6.0
• Microsoft Visual C++, 32-bit Editions, versions 5.0, 6.0

SYMPTOMS

A control created with the Microsoft Active Template Library (ATL) using the ATL COM AppWizard works properly in Visual C++. It also functions in Visual Basic, except when you try to save the Visual Basic project, you might get the following error message:

System Error &H80070057 (-2147024809): The parameter is incorrect.

CAUSE

When Visual Basic saves a form, it saves the persistent properties of all the controls on the form using a PropertyBag. The error message mentioned above means that Visual Basic detects an incorrect property name specified by the control.

RESOLUTION

Use correct property names in the PROP_ENTRY macro of your ATL control. Visual Basic does not support blank spaces in the string names of properties, so your property names should avoid embedded spaces.

STATUS

This behavior is by design.

MORE INFORMATION

Steps to Reproduce Behavior

1. Use the ATLBUTTON sample that ships with Visual Studio to reproduce the error. Go to your Visual Studio CD-ROM and copy the sample files from the \DEVSTUDIO\VC\Sample\Atl\ATLBUTTON directory to your hard drive.



2. Build the sample with Visual C++. The control is automatically registered.



3. Now start Visual Basic and create a Standard EXE project. Form1 is created by default.



4. Choose Components from the Project menu and add the ATLBUTTON control to the control ToolBox by selecting ATLBUTTON and clicking OK.



5. Add an instance of the control to Form1.



6. Save the project. You should get an error message.

Steps to Solve the problem

1. Open the file AtlButton.h and change the following section:

   
         BEGIN_PROPERTY_MAP(CAtlButton)
            PROP_ENTRY("Static Image", 0, CLSID_NULL)
            PROP_ENTRY("Hover Image", 1, CLSID_NULL)
            PROP_ENTRY("Push Image", 2, CLSID_NULL)
         END_PROPERTY_MAP() 

   to:

   
         BEGIN_PROPERTY_MAP(CAtlButton)
            PROP_ENTRY("StaticImage", 0, CLSID_NULL)
            PROP_ENTRY("HoverImage", 1, CLSID_NULL)
            PROP_ENTRY("PushImage", 2, CLSID_NULL)
         END_PROPERTY_MAP() 

   i.e. delete all spaces in the property names.



2. Rebuild the ATL project and repeat steps 3 - 6 above. This time it works correctly.

Additional query words:

Keywords : kberrmsg kbActiveX kbATL kbCOMt kbVBp500 kbVBp600 kbVC500 kbVC600 kbGrpVB
Version : WINDOWS:5.0,6.0; WINNT:5.0,6.0
Platform : WINDOWS winnt
Issue type : kbprb