70-483 試験問題を無料オンラインアクセス

You are implementing a new method named ProcessData. The ProcessData() method calls a third-party component that performs a long-running operation to retrieve stock information from a web service.
The third party component uses the IAsyncRcsult pattern to signal completion of the long-running operation so that the UI can be updated with the new values.
You need to ensure that the calling code handles the long-running operation as a 5ystem.Threading_Tasks.Task object to avoid blocking the Ul thread.
Which two actions should you perform? (Each correct answer presents part of the solution. Choose two.)

• A.Create a TaskCompletionSource<T> object.
• B.Apply the following attribute to the ProcessDataO method signature:
  [Methodlmpl (MetrhodlmplOptiions . Synchronized) ]
• C.Apply the async modifier to the ProcessData() method signature.
• D.Call the component by using the TaskFactory FromAsync() method.

You need to write a method that retrieves data from a Microsoft Access 2013 database. The method must meet the following requirements:
* Be read-only.
* Be able to use the data before the entire data set is retrieved.
* Minimize the amount of system overhead and the amount of memory usage.
Which type of object should you use in the method?

• A.unTyped DataSet
• B.DbDataAdapter
• C.DataContext
• D.DbDataReader

You use the Task.Run() method to launch a long-running data processing operation. The data processing operation often fails in times of heavy network congestion.
If the data processing operation fails, a second operation must clean up any results of the first operation.
You need to ensure that the second operation is invoked only if the data processing operation throws an unhandled exception.
What should you do?

• A.Create a task within the operation, and set the Task.StartOnError property to true.
• B.Use the TaskScheduler class to create a task and call the TryExecuteTask() method on the class.
• C.Create a task by calling the Task.ContinueWith() method.
• D.Create a TaskFactory object and call the ContinueWhenAll() method of the object.

You are developing a class named ExtensionMethods.
You need to ensure that the ExtensionMethods class implements the IsEmail() extension method on string objects.
How should you complete the relevant code? (To answer, drag the appropriate code segments to the correct locations in the answer area. Each code segment may be used once, more than once, or not at all. You may need to drag the split bar between panes or scroll to view content.)

正解：

Explanation:
Extensions must be in a static class as it kind of a shared source of extension methods. You do not instantiate the class.
The key word "this" is simply a syntax how you tell the compiler, that your method IsUrl is extension for the String object

You have the following C# code.

What is the output of the code?

• A.3
• B.-3
• C.-4
• D.7
• E.2