Your WPF application needs to display a list of employees and their performance ratings from a database. Explain how you would implement data binding with sorting and filtering capabilities.
- Data binding with CollectionViewSource and ICollectionView interface
- Data binding with Entity Framework Core
- Data binding with DataGrid control
- Data binding with DataSet
To implement data binding with sorting and filtering capabilities in a WPF application, you can use CollectionViewSource along with the ICollectionView interface. CollectionViewSource provides a wrapper around your data source, while ICollectionView offers sorting and filtering functionalities. You can bind your employee data to a CollectionViewSource and then apply sorting and filtering criteria through the ICollectionView interface, allowing users to interactively sort and filter the employee list in the UI. This approach provides a flexible and efficient way to handle sorting and filtering requirements while maintaining a clean separation between UI and data logic. The other options may not offer built-in support for dynamic sorting and filtering or may require more manual coding effort.
LINQ queries can be performed on various data sources, including collections, arrays, and ___________.
- Databases
- JSON Files
- Web Services
- XML Documents
LINQ allows developers to perform queries not only on collections and arrays but also on XML documents, enabling versatile data manipulation.
Explain the concept of "lazy loading" in Entity Framework and its impact on performance.
- Automatic loading of related entities without any explicit request, improves performance
- Deferred loading of related entities until they are specifically requested, can lead to excessive database queries
- Eager loading of all related entities upfront, reducing database round-trips
- Manual loading of related entities using custom queries, enhances control over data retrieval
Lazy loading in Entity Framework refers to the practice of deferring the loading of related entities until they are accessed. While this can lead to excessive database queries if not managed properly, it helps improve performance by only loading the necessary data when needed.
The ExecuteScalar method is suitable for retrieving a ___________ value from a SELECT statement.
- Single
- Multiple
- Aggregate
- Composite
The correct option is Option 1: Single. The ExecuteScalar method in ADO.NET is used to execute a SQL query that returns a single value, such as a count, sum, average, or any other aggregate or scalar value, typically from a SELECT statement with a WHERE clause.
Which LINQ operator is used to filter elements in a sequence based on a specified condition?
- Filter
- OrderBy
- Select
- Where
The Where operator is used to filter elements in a sequence based on a specified condition. It allows you to specify a predicate function that determines which elements to include in the result sequence.
The CommandType property can be set to ___________ when executing a text-based SQL query.
- StoredProcedure
- TableDirect
- Text
- Function
The correct option is Text. When executing a text-based SQL query using ADO.NET, you can set the CommandType property of the command object to Text. This indicates that the command text contains a SQL query statement to be executed directly against the database. Setting the CommandType to Text is appropriate for executing dynamic SQL queries or stored procedures that return rows.
Scenario: Your project involves interacting with a SQL Server database. Which LINQ technology is the most appropriate choice for querying and manipulating data in the database?
- LINQ to Entities
- LINQ to Objects
- LINQ to SQL
- LINQ to XML
LINQ to SQL is specifically designed for querying and manipulating data in SQL Server databases. It allows developers to write LINQ queries directly against the database entities, providing a strongly-typed approach to database access and manipulation.
Which ADO.NET class represents a command object for executing SQL queries and stored procedures in SQL Server?
- SqlCommand
- SqlConnection
- SqlDataAdapter
- SqlDataReader
The SqlCommand class in ADO.NET represents a command object specifically designed for executing SQL queries and stored procedures in SQL Server. It provides methods for executing commands and retrieving results from the database.
When using data binding in ADO.NET, what is the role of the DataSource property?
- Binds the data to the UI control
- Executes SQL commands
- Specifies the connection string to the database
- Specifies the name of the database table
The DataSource property in ADO.NET is used to bind data from a data source, such as a dataset or data table, to a UI control, such as a DataGridView or ListBox. It establishes the connection between the data source and the control, enabling the display and manipulation of data in the user interface.
What does LINQ stand for in the context of LINQ to DataSet?
- Language-Integrated Query
- Lightweight Interface for .NET Queries
- Logical Interface for Network Queries
- Longitudinal Inquisitive Query
In LINQ to DataSet, LINQ stands for Language-Integrated Query, which allows developers to query datasets using a syntax similar to SQL within the .NET programming languages such as C# and VB.NET. This provides a more intuitive and readable way to interact with data stored in memory or databases.