If you upgrade the RTM version of Visual Studio 2008 with the SP1 service pack distribution, the EntityDataSource control does not appear in the Data group of the Web project Toolbox by default. To add the control to the Toolbox:

  1. Open Visual Studio
  2. Open or create a Web Application or Project.
  3. Make sure the Toolbox tool window is visible.
  4. Right click on the Toolbox, in the Data group and click on the "Choose Items…"  option.
  5. Wait for the "Choose Toolbox Items"  window to appear.
  6. Scroll down in the list of components under the ".NET Framework Components"  tab until you find "EntityDataSource"
  7. Ensure the checkbox is marked next to the EntityDataSource component and click on the OK button.

If you cannot see “EntityDataSource” in the list, you may need to add the assembly manually. To do that, click on the “Browse” button on the “Choose Toolbox Items” window. Then browse for the System.Web.Entity.dll under “C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5” or the equivalent folder in your configuration.

 

Diego Vega
Program Manager, ADO.NET