System.Activities tab, Choose Toolbox Items dialog box

This tab of the Choose Toolbox Items dialog box displays a list of Windows Workflow Foundation (WF) activities, templates, and items available to you. To display this list, select Choose Toolbox Items from the Tools menu or by right-clicking the Toolbox and selecting Choose Items to display the Choose Toolbox Items dialog box, and then select its System.Activities tab. Out of the box, the list contains workflow activities from System.Activities, System.ServiceModel.Activities, and System.Activities.Core.Presentation assemblies; however, only the system-provided activities shown and activities added through other assemblies displayed in the Toolbox are checked by default. Recently added activities are automatically checked and appear in the Toolbox when you click OK on the dialog box. Also, these items appear in the Toolbox under a new category that corresponds to the namespace where the activity/item/template resides.


If you try to add an assembly that does not contain any workflow activities, an error dialog is displayed that explains that the assembly does not contain any activities.

This dialog box is project agnostic and hence the System.Activities tab continues to show up in standalone XAML or a non-workflow project type.

Filtering is done on each tab, and it's not possible to add workflow activities through the .NET Component tab. Add them through the System.Activities tab itself.

You can uncheck any items you do not want to see in the Toolbox from this dialog tab, or alternatively, you can do so using the Delete right-click menu option in the Toolbox and de-referencing an assembly does not remove the item from the Toolbox.

Instantiating the activity, by dragging and dropping it on the designer adds the assembly that contains the item to the referenced assemblies list automatically. Also if the activity references an assembly C, it does not add C to the referenced assembly list. Assembly C has to be in the GAC or the same directory as the activity B. In the standalone case, the assembly has to be in GAC or the Probe paths of VS. Only then can you drag and drop the activity on the workflow designer surface.

Toolbox settings are saved by default as user options, so the next time, when you open the Toolbox, it displays your customized list of workflow activities. One side effect of this is that if you have added your specific domain items to the Toolbox through the Choose Toolbox Items dialog box, you still continue to see those items when you are working in a Workflow Console Application as well. If you do not want to see them, then delete them using the right-click menu or uncheck them through the Choose Toolbox Items dialog box as noted previously.

The columns in this dialog box contain the following information:

Lists the names of the workflow activities currently registered on your local machine.

Displays the hierarchy of the .NET namespace that defines the structure of the activity.

Assembly Name
Displays the name and version of the .NET assembly that contains the activity.

Displays the location of the .NET assembly that contains the workflow activities. The default location for all assemblies is the Global Assembly Cache.

To sort the components listed, select any column heading.