PRB: Use of Data-Bound Controls is Version Dependent

 Last reviewed: August 7, 1997
Article ID: Q168449
The information in this article applies to:
  • Microsoft Visual C++, 32-bit Editions, versions 4.2, 4.2b, 5.0

SYMPTOMS

Loading Visual C++ 5.0 on a system that has Visual C++ 4.x installed will cause numerous DLLs, OCXs, and other components to be overwritten. One set of components that is updated are the data-bound controls.

  • DBGrid
  • DBListBox
  • DBComboBox
  • Remote Data Control

Although it is possible to load Visual C++ 4.x and 5.0 on the same system in different directories, Visual C++ 4.x will have trouble displaying the data-bound controls properties.

Displaying the "All" Tab on Database Controls such as Microsoft Data Combo and Microsoft Masked Edit Box shows <Property unknown> after having installed Visual C++ 5.0. Normally, you will see Datasource, field properties, etc.

CAUSE

Visual C++ 5.0 installs upgrades of the data-bound controls that have the same file names as the versions that ship with Visual C++ 4.x.

RESOLUTION

If you want to work with Visual C++ 4.2, replace the appropriate controls in your system32 from the version 4.2 redist\ocx directory (in this case, MSMASK32.OCX DBLIST32.OCX).

The Property Dialog Headings for these controls have also changed to Microsoft DBCombo, version 5.0 and Microsoft Masked Edit Box version 5, rather than Microsoft DBCombo and Microsoft Masked Edit Box. Creating a new project exhibits the same problem. This makes is somewhat difficult to use these controls.

There are three controls that have the same name as the previous version and therefore overwrite the version that works with version 4.2:

  • DBGrid32.ocx
  • DBList32.ocx
  • MSMask32.ocx

STATUS

This behavior is by design.

MORE INFORMATION

It is not possible to work with version 5.0 data-bound controls in Visual C++ 4.x or with version 4.x data-bound controls in Visual C++ 5.0. The data-bound controls have been changed in these two versions.

It is highly recommended that you chose between versions 4.2 or 5.0 when working with database applications that use the data-bound controls.

Although this is problem in the design interface, the newer 5.0 controls can be used by older 4.2 applications at run-time.

REFERENCES

VCREAD.HTM that ships with Visual C++ 5.0 

Keywords          : MfcDAO MfcDatabase kbprb
Version           : 4.2 4.20b 5.0
Platform          : NT WINDOWS

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Last reviewed: August 7, 1997
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