Viewing LINQ Results

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You can view the result of a LINQ statement by using DataTips, the Watch window, and the QuickWatch dialog box. When you use a source window, you can pause the pointer on a query in the source window and a DataTip will appear. You can copy a LINQ variable and paste it into the Watch window or QuickWatch dialog box.

In LINQ, a query is not evaluated when it is created or declared, but only when the query is used. Therefore, the query does not have a value until it is evaluated. For a full description of query creation and evaluation, see Introduction to LINQ Queries or Writing Your First LINQ Query (Visual Basic).

To display the result of a query, the debugger must evaluate it. This implicit evaluation, which occurs when you view a LINQ query result in the debugger, has some effects you should consider:

• Each evaluation of the query takes time. Expanding the results node takes time.. For some queries, repeated evaluation might result in a noticeable performance penalty.

• Evaluating a query can result in side effects, which are changes to the value of data or the state of your program. Not all queries have side effects. To determine whether a query may be safely evaluated without side effects, you must understand the code that implements the query.

See Also

Concepts

Side Effects and Expressions

Exception Handling (Debugging)

Other Resources

Debugging LINQ