EFCoreLinqExpressionProjection

This project enables the reuse of LINQ expression logic in projections. This is a fork of EFLinqExpressionProjection but with support for queries from Entity Framework Core.

Usage

To use, call extension method AsExpressionProjectable() on the collection queried, and when projecting call the extension method Project<TIn, TResult>(TIn) (on a field, method or any other code element) returning a selector of type Expression<Func<TIn, TResult>>. TIn and TResult can be anything, and they will both be inferred by the compiler meaning that usages of Project() do not have to explicitly specify them.

Example:

Expression<Func<Project, double?>> averageEffectiveAreaExpression =
  proj => proj.Subprojects.Average(sp => sp.Area);

var projects = await context.Projects
  .AsExpressionProjectable()
  .Select(p => new 
  {
    Project = p,
    AverageEffectiveArea = averageEffectiveAreaExpression.Project(p)
  })
  .ToListAsync();

Installation

Find this on NuGet: https://www.nuget.org/packages/EFCoreLinqExpressionProjection