The ConnectionStringsExpressionEditor.GetExpressionEditorSheet(string, IServiceProvider) method returns an editor sheet implementation for connection string expressions. The editor sheet for connection string expressions allows users to select a connection name and type, based on the current connection strings that are defined in the connectionStrings section of the Web configuration file. Once users have selected the connection expression properties, the editor sheet implementation combines the connection name and type into a connection string expression, which is returned to the visual designer.