It is said that it takes three iterations to make a software application right and it seems to be correct: it was not until Visual Basic 3.0 when people started to use it in serious applications, it was not until MZ-Tools 3.0 when my add-in was widely used and it was not until .NET Framework 2.0 (which is actually the 3rd iteration after versions 1.0 and 1.1) when Microsoft did it right with .NET Data Providers, making it possible to use provider factories and base classes to write database-independent code. If I was fascinated with source code control providers as I posted recently, I am even more fascinated with data providers, since the times of ODBC around 1995. It happens that for my first job I had to learn Visual Basic 3.0 and ODBC in two weeks…and before becoming interested in the extensibility of IDEs around 2000, I was an expert in ODBC/OLEDB technologies, maybe some of you still remember me in the ODBC newsgroups around 1997-1999… anyway, to the point:

You may have noticed that Visual Studio .NET 2002 and 2003 used OLE DB providers and not the new ADO.NET data providers in the Data Connection dialog of the Server Explorer. Inexplicably, despite the previous experience with ODBC and OLEDB, Microsoft did not provide a standard way to enumerate .NET data providers or to show a standard connection dialog in .NET Frameworks 1.0 and 1.1. It was in .NET Framework 2.0 when the new ADO.NET 2.0 providers provide connection string builders, connection factories, etc. You can learn more about it in What’s new in ADO.NET 2.0. Visual Studio 2005 leverages the new capabilities of ADO.NET 2.0 providers and in turn provides good extensibility to use any ADO.NET 2.0 data provider in the data design-time experience of the IDE, thanks to the Data Designer Extensibility (DDEX). Using DDEX Visual Studio 2005 provides a new Data Connection dialog based on ADO.NET providers, not OLEDB providers. You can read a very good Introduction to Visual Studio Data Designer Extensibility (DDEX) and then you can read the DDEX SDK documentation. With DDEX you can make any ADO.NET 2.0 provider appear in the data connection dialog as explained in those links. Also, you can use that dialog from your own code (an add-in or VS package) and since this is a common question but it does not seem to be addressed in the documentation, I have written an article about it:

HOWTO: Using the Choose Data Source dialog of Visual Studio 2005 from your own code
http://www.mztools.com/articles/2007/MZ011.htm