You are designing a Windows Presentation Foundation (WPF) application by using Microsoft .NET Framework 4, Microsoft Visual Studio 2010, and Microsoft SQL Server 2008.
You have designed the application to use the ADO.NET Entity Framework for the Data Access Layer (DAL).
You have designed the user interface (UI) of the application by using the Model-View-ViewModel (M-V-VM) pattern.
The middle tier of the application is designed by using Windows Communication Foundation (WCF).
The database schema changes often. The DAL entity objects are required to be referenced from the middle tier and the ViewModel layer of the UI.
You need to ensure that the DAL entity objects are updated when the database schema changes.
What should you do?

• A. Create typed DataSets.
• B. Create persistent-aware objects.
• C. Create an observable collection of objects.
• D. Create persistent-ignorant objects.

You are designing an n-tier solution that includes a Windows Presentation Foundation (WPF) client application. The WPF application connects to a middle-tier server that runs the data access layer.
The data access layer connects to a Microsoft SQL Server 2008 database and to a mainframe-based database.

• A. Add the connection string information for the databases to the configuration file for the WPF application. Implement a database factory class from within the WPF application.
• B. Add the connection string information for the databases to the configuration file for the WPF application. Implement one class in the WPF application for each data source.
• C. Create a data access layer class that uses a database factory class to access all databases. Add the connection string information for the databases to the configuration file for the data access layer class.
• D. Create a data access layer class that uses a database factory class to access all databases. Add the connection string information for the databases to the configuration file for the WPF application.

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

You are designing a Windows Presentation Foundation (WPF) application.
You have the following requirements:
- Run client-side validation tests on a large result set from a Microsoft SQL Server 2008 database. - Validate each row of data without storing the entire result set in memory.
You need to recommend a data access technology.
What should you recommend?

• A. LINQ to Entities using the ElementAt() method
• B. ADO.NET using SqIDataAdapter objects and DataSet objects
• C. ADO.NET using SqIDataReader objects
• D. LINQ to SQL using the ElementAt() method

You are reviewing an existing Windows application that uses .NET Framework 4.
When the user clicks a button, the application sequentially processes thousands of image
files contained in a directory.
The user interface becomes unresponsive while the application processes the files.
You have the following requirements:
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Modify the button's click event.
Increase application throughput by processing multiple image files concurrently.
Ensure that the user interface remains responsive while the application processes
the image files.
You need to recommend an approach for meeting the requirements.
What should you recommend?

• A. Use the Parallel.ForEach() method to process the images concurrently.
• B. Iterate over the image files by using the Parallel.ForEach() method. For each image file, start a separate thread that processes the image file, by using the Thread.Start()method.
• C. Use the ThreadPool.QueueUserWorkItem() method to queue up a single work item that uses the Parallel.ForEach () method to process the image files concurrently.
• D. Iterate over the image files. For each image file, use the Process.Start() method to launch a console application that processes the image file.