FIX: GetPropertyInfo Not Returning Correct Values for Default Case

View products that this article applies to.

This article was previously published under Q217183

SYMPTOMS

After creating an OLE DB Provider with the ATL Wizard in Visual C++ 6.0, the IDBProperties::GetPropertyInfo returns all of the DATASOURCEINFO properties rather than the initialization properties; also, the GUID returned in the DBPROPINFOSET structure is DBPROPSET_DBINITALL.

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CAUSE

This problem is caused by a bug in IDBPropertiesImpl::GetPropertyInfo(), implemented in the ATL OLE DB header file Atldb.h.

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RESOLUTION

Install Visual Studio Service Pack 3 to get a corrected version of Atldb.h.

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STATUS

Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article.

This bug was corrected in Visual Studio 6.0 Service Pack 3. For more information about Visual Studio service packs, please see the following articles in the Microsoft Knowledge Base:

194022 INFO: Visual Studio 6.0 Service Packs, What, Where, Why (http://support.microsoft.com/kb/194022/EN-US/ )

194295 HOWTO: Tell That Visual Studio 6.0 Service Packs Are Installed (http://support.microsoft.com/kb/194295/EN-US/ )

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MORE INFORMATION

According to the OLE DB documentation:

If cPropertyIDSets is zero, the provider ignores rgPropertyIDSets. When called on the enumerator, the provider returns information about all properties in the Initialization property group. When called on the data source object, if the data source object has not been initialized, the provider returns information about all properties in the Initialization property group.

Also regarding the GUID returned in DBPROPINFOSET and the special GUIDs like DBPROPSET_DBINITALL:

These GUIDs are not returned in the guidPropertySet element of the DBPROPINFOSET structures returned in rgPropertyInfoSets. Instead, the GUID of the property set to which the property belongs is returned.

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Steps to Reproduce Behavior

Create a new ATL COM project using the ATL COM AppWizard, and accept all default settings.
From the Insert menu, click New ATL Object.
Select Data Access in the left pane, then Provider in the list of objects.
Give the object a name.
Save and compile the project.
Debug the project and when asked for an executable, specify ITest.exe from the MS Data Access SDK (MSDASDK). If you need to install the MSDASDK, it can be found on CD 2 of Visual C++ or Visual Studio, under the DASDK directory.
Once ITest is running, right-click Win32[oledb Providers] and select CoCreateInstance.
Double-click the Value column of the first row to activate a drop down list of providers.
Select your provider from the list.
Select the ICW menu and then Execute.
Right-click your provider in the Object window and select IDBProperties and then GetPropertInfo from the sub-menu.
Ensure that cPropertyIDSets is set to 0 (zero).
Allocate memory for pcPropertyInfoSets by right-clicking the Value column and selecting AllocateMemory from the context menu.
Ensure prgPropertInfoSets and ppDescBuffer have memory allocated; you should see &NULL rather than NULL.
Select the ICW menu and then Execute.
Look at the results in the Output window.

RESULTS: You will get back all of the DATASOURCEINFO properties rather than the initialization properties; also, the GUID returned in the DBPROPINFOSET structure is DBPROPSET_DBINITALL.

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