1. A computer-readable hardware device having computer-executable instructions for causing a computer to perform steps comprising: enabling a command interpreter to be used at design time by a user to test a functionality of an application from within a software application design environment; enabling a selected object to be sent from a visual tree to the command interpreter, wherein the visual tree is generated by recursively traversing through child objects of the selected object, and obtaining one or more properties for each child object via a reflection process that inspects an object type; displaying the visual tree to the user in the software application design environment; synchronizing the visual tree with a current design view in the software application design environment; setting the selected object as a current object in the command interpreter upon being received from the visual tree; and performing an operation to test the functionality of the application on a particular command interpreter object designated as the current object during design time, the operation performed via at least one command entered directly into the command interpreter and without a compilation of the application.