LINQ
LINQ is a .NET language-integrated query technology for querying and transforming data from collections and other data sources.
.NET in Action, Second Edition
Language Integrated Query (LINQ) is a .NET language-integrated query technology for querying collections and data sources with a common syntax.
- How it is used
- Uses LINQ to shape a reflected font collection for an ASP.NET Core service endpoint.
- How deep it goes
- Works through projection, method translation, paging, filtering, and sorting; defers database querying to a later chapter.
- Examples
- Shows reflected font names, equivalent query and method forms, and endpoint handlers with paging and optional filters.
- What you can do after
- Apply it via C# LINQ and ASP.NET Core minimal APIs to project, filter, sort, and page a collection.
Building Web APIs with ASP.NET Core
LINQ is a .NET language-integrated query facility that provides a uniform syntax and API for querying and transforming data from different sources.
- How it is used
- Supports CRUD operations by querying and transforming database-backed objects through a unified C# API.
- How deep it goes
- Traces syntax, operators, interfaces, expression trees, SQL translation, chaining, and deferred execution.
- Examples
- Uses board-game arrays, year filtering, chained ordering, DbSet queries, expression trees, and ToArray() materialization.
- What you can do after
- Apply it via EF Core to implement filtering, ordering, and other CRUD queries without writing each SQL statement manually.
Read how Building Web APIs with ASP.NET Core explains LINQ →
Pro ASP.NET Core 7, Tenth Edition
LINQ is the .NET language-integrated query capability for expressing queries and filtering operations over data sources.
- How it is used
- Queries Entity Framework Core data for endpoint responses and Blazor component output.
- How deep it goes
- Works through an endpoint lookup and generated SQL, then diagnoses repeated execution; does not teach LINQ syntax from zero.
- Examples
- Uses a stored sum lookup, its SQL command log, and duplicate queries from a Blazor people list.
- What you can do after
- Diagnose/debug with it by inspecting generated SQL and identifying queries repeated by endpoint requests or component renders.
Related concepts
- Entity Framework Coreused by · Entity Framework Core is a cross-platform object-relational mapping framework for .NET that enables applications to query and persist data through .NET objects and APIs.
- orderBy clauseused by · An orderBy clause or operation specifies the key or criteria by which query results or sequence elements are ordered.
- IEnumerable<T>uses · IEnumerable<T> is a .NET generic interface representing a sequence whose elements of type T can be traversed through an enumerator.
- blockused by · A code block is a grouped region of code treated as a unit, with boundaries and scope or execution behavior determined by its language or context.
- SQLproduces · SQL is a standardized declarative language for defining, querying, and manipulating data and structures in relational database systems.
- CRUDused by · CRUD is the set of data-management operations for creating, reading, updating, and deleting records or resources.
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