You are designing a Windows Forms application that allows users to search a product catalog and place orders.
You have the following requirements:
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Display a progress indicator while the application is searching the catalog. Ensure that users can cancel search operations.
You need to recommend an approach that meets the requirements.
What should you recommend?

• A. Execute the search on the user interface thread. Provide a Cancel button to cancel the search.
• B. Use a BackgroundWorker component to perform the search.
• C. Implement the search as a Windows Communication Foundation (WCF) service by usingthe AsyncPattern property of the OperationContractattribute.
• D. Implement the search as a duplex service.

You are designing a complex and critical Windows desktop application by using Microsoft .NET Framework 4 and Microsoft Visual Studio 2010.
You plan to implement a logging strategy for the application.
You need to record all unexpected errors that occur in the application.
What should you do?

• A. Subscribe to the unhandled exception event handler for the application's dispatcher on the main application thread.
  Record relevant application-specific information to an external log.
• B. Create a global WIN 32 unhandled exception filter.
  Record relevant application-specific information to an external log from within the filter.
• C. Create a generic catch (Exception e) block in the Main method of the application.
  Record relevant application-specific information to a log in the Main method.
• D. Subscribe to the unhandled exception event handler for the AppDomain object.
  Record relevant application-specific information to an external log.

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You are designing a .NET Framework 4 solution. The solution contains a Windows Presentation Foundation (WPF) application and a Windows Communication Foundation (WCF) Web service.
The WPF application uses the WCF Web service to store data in a Microsoft SQL Server 2008 database.
You have the following requirements:
Ensure that the WPF application functions while users' computers are offline.
Minimize the time spent sending data to the WCF Web service.
Minimize disk space requirements for data storage.
You need to recommend an approach for synchronizing data between the WPF application and the database.
Which two actions should you recommend? (Each correct answer presents part of the solution. Choose two.)

• A. Store data in custom business objects. Serialize data locally by using custom serialization.
• B. Store data in DataSet objects. Serialize data locally by using XML serialization.
• C. Create a local caching solution that periodically checks for Internet connectivity, uses local memory, and batches changes to the WCF Web service.
• D. Create a local caching solution that periodically checks for Internet connectivity and writes directly to the local data store and to the WCF Web service.

You are designing an application by using Windows Presentation Foundation (WPF) and
Microsoft .NET Framework 4.
The user interface (UI) tier of the application will be implemented in WPF.
The middle tier of the application is implemented by using an existing COM component.
The middle tier contains a long-running method named ProcessDatA.
You need to ensure that users can continue to use the UI while ProcessData is running.
What should you do?

• A. Use an asynchronous worker thread to call ProcessDatA.
• B. Call the Run method of the Dispatcher class before invoking ProcessDat
• C. Use the Invoke method of the Dispatcher class to call ProcessDatA.
• D. Call the DoEvents method of the Application class before invoking ProcessDatA.