AutoQuery.Generator

📖 Documentation site · NuGet · Changelog

Compile-time query composition for IQueryable<T> via Roslyn incremental source generators.

Add [QuerySpec(typeof(Product))] to a partial query class and AutoQuery.Generator emits strongly-typed Apply(IQueryable<Product>), BindFromQuery(...), and FromQuery(...) methods at build time. No reflection. No runtime scanning. AOT-friendly.

usingAutoQuery;usingSystem.Linq;[QuerySpec(typeof(Product))]publicpartialclassProductQuery{publicstring?Name{get;set;}publicdecimal?MinPrice{get;set;}publicdecimal?MaxPrice{get;set;}[QuerySort]publicstring?SortBy{get;set;}publicboolSortDescending{get;set;}publicintPageNumber{get;set;}=1;publicintPageSize{get;set;}=20;}varfiltered=newProductQuery{Name="Laptop",MinPrice=500,SortBy="Name",PageNumber=1,PageSize=10,}.Apply(products);// Or bind directly from HTTP query-string values:varrequestQuery=newDictionary<string,string?>{["Name"]="Laptop",["MinPrice"]="500",["SortBy"]="Name",["PageNumber"]="1",["PageSize"]="10"};varbound=ProductQuery.FromQuery(requestQuery);varfilteredFromQuery=bound.Apply(products);

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Installation

dotnet add package AutoQuery.Generator

Targets netstandard2.0 and works with modern SDK-style .NET projects.

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Quick start

1. Define an entity and query spec

usingAutoQuery;publicsealedclassProduct{publicstring?Name{get;set;}publicdecimalPrice{get;set;}publicboolIsActive{get;set;}}[QuerySpec(typeof(Product))]publicpartialclassProductQuery{publicstring?Name{get;set;}publicdecimal?MinPrice{get;set;}publicbool?IsActive{get;set;}}

2. Use the generated Apply method

IQueryable<Product>query=dbContext.Products;varspec=newProductQuery{Name="Phone",MinPrice=100,IsActive=true};varresult=spec.Apply(query);

3. Bind directly from query-string values

usingAutoQuery;[QuerySpec(typeof(Product))]publicpartialclassProductQuery{publicstring?Name{get;set;}publicdecimal?MinPrice{get;set;}[QuerySort]publicstring?SortBy{get;set;}publicboolSortDescending{get;set;}publicintPageNumber{get;set;}=1;publicintPageSize{get;set;}=20;}// Works with Dictionary<string, string?>varquery=ProductQuery.FromQuery(newDictionary<string,string?>{["Name"]="Laptop",["MinPrice"]="500",["SortBy"]="Name",["PageNumber"]="1",["PageSize"]="10"});// Also works with ASP.NET Core Request.Query without taking an ASP.NET Core package dependency.app.MapGet("/products",(AppDbContextdb,HttpRequestrequest)=>{varspec=ProductQuery.FromQuery(request.Query);returnspec.Apply(db.Products);});

Unknown keys are ignored, malformed values are skipped, and successful conversions use invariant culture for numeric/date parsing plus case-insensitive enum parsing.

Generated output resembles:

publicpartialclassProductQuery{publicIQueryable<global::YourApp.Product>Apply(IQueryable<global::YourApp.Product>query){if(Nameis not null)query=query.Where(x =>x.Name!=null&&x.Name.Contains(Name));if(MinPriceis not null)query=query.Where(x =>x.Price>=MinPrice.Value);if(IsActiveis not null)query=query.Where(x =>x.IsActive==IsActive.Value);returnquery;}}

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Attributes

[QuerySpec(typeof(TEntity))]

Marks a partial class as a query spec for the target entity.

[QuerySpec(typeof(Order))]publicpartialclassOrderQuery{}

[QueryFilter("x => x.Category.Name == value")]

Overrides the default convention and uses your custom LINQ predicate expression. The token value is replaced with the query property access.

[QueryFilter("x => x.Category.Name == value")]publicstring?CategoryName{get;set;}

[QueryIgnore]

Skips a property entirely.

[QueryIgnore]publicstring?DebugOnly{get;set;}

[QuerySort]

Marks a string? property as the requested sort field.

[QuerySort]publicstring?SortBy{get;set;}publicboolSortDescending{get;set;}

[QueryPage]

Marks pagination properties when you are not using the conventional names PageNumber and PageSize.

[QueryPage]publicintResultsPageNumber{get;set;}=1;[QueryPage]publicintResultsPageSize{get;set;}=25;

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Convention-based filters

Nullable properties become filters automatically unless excluded.

Spec property	Generated predicate
string? Name	x => x.Name != null && x.Name.Contains(Name)
bool? IsActive	x => x.IsActive == IsActive.Value
int? CategoryId	x => x.CategoryId == CategoryId.Value
decimal? MinPrice	x => x.Price >= MinPrice.Value
decimal? MaxPrice	x => x.Price <= MaxPrice.Value
DateTime? CreatedFrom	x => x.Created >= CreatedFrom.Value
DateTime? CreatedTo	x => x.Created <= CreatedTo.Value

Prefix/suffix conventions:

• Min... → >=
• Max... → <=
• ...From → >=
• ...To → <=

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Sorting

When the spec contains a [QuerySort] string property and a bool property named SortDescending or IsDescending, AutoQuery emits switch-based sorting.

[QuerySpec(typeof(Product))]publicpartialclassProductQuery{publicstring?Name{get;set;}publicdecimal?Price{get;set;}[QuerySort]publicstring?SortBy{get;set;}publicboolSortDescending{get;set;}}

Generated shape:

if(SortByis not null){query=(SortBy,SortDescending)switch{("Name",false)=>query.OrderBy(x =>x.Name),("Name",true)=>query.OrderByDescending(x =>x.Name),("Price",false)=>query.OrderBy(x =>x.Price),("Price",true)=>query.OrderByDescending(x =>x.Price),
_ =>query};}

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Pagination

When PageNumber and PageSize are present (or [QueryPage] annotated equivalents are detected), AutoQuery emits:

query=query.Skip((PageNumber-1)*PageSize).Take(PageSize);

Example:

[QuerySpec(typeof(Product))]publicpartialclassProductQuery{publicstring?Name{get;set;}publicintPageNumber{get;set;}=1;publicintPageSize{get;set;}=20;}

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HTTP query-string binding

For every [QuerySpec] class with writable supported properties, AutoQuery emits:

publicvoidBindFromQuery(IEnumerable<KeyValuePair<string,string?>>query);publicvoidBindFromQuery<TValue>(IEnumerable<KeyValuePair<string,TValue>>query)whereTValue:IEnumerable<string>;publicstaticProductQueryFromQuery(IEnumerable<KeyValuePair<string,string?>>query);publicstaticProductQueryFromQuery<TValue>(IEnumerable<KeyValuePair<string,TValue>>query)whereTValue:IEnumerable<string>;

Supported property conversions:

• string
• numeric types and nullable numeric types
• bool / bool?
• DateTime / DateTime?
• enums and nullable enums

The generic overload is what lets Request.Query bind cleanly: IQueryCollection enumerates as KeyValuePair<string, StringValues>, and StringValues implements IEnumerable<string>, so no AutoQuery runtime dependency on ASP.NET Core is required.

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Diagnostics

Id	Severity	Description
AQ001	Error	[QuerySpec] entity type could not be resolved.
AQ002	Error	[QuerySpec] target class must be declared partial.
AQ003	Warning	Spec has no filterable properties.

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Comparison

Capability	AutoQuery.Generator	Manual LINQ	Ardalis.Specification
Compile-time generated Apply method	✅	❌	❌
Compile-time generated query-string binding	✅	❌	❌
Reflection-free	✅	✅	Usually ✅
Convention filters from DTO-like class	✅	❌	❌
Custom inline filter expressions	✅	Manual only	Via handwritten spec logic
Built-in sort switch generation	✅	Manual only	Manual only
Built-in pagination generation	✅	Manual only	Manual only
Runtime abstraction dependency	None	None	Package dependency

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Also by the same author

🌐 Full suite overview: swevo.github.io

Package	Description
AutoWire	Compile-time DI auto-registration — [Scoped]/[Singleton]/[Transient] generates IServiceCollection code. Zero reflection.
AutoMap.Generator	Compile-time object mapping — [Map(typeof(Dto))] generates ToDto() extension methods. Zero reflection, AOT-safe.
AutoValidate.Generator	Compile-time FluentValidation wiring — discovers AbstractValidator<T> subclasses and generates AddValidators().
AutoResult.Generator	Compile-time Result<T> monad — [TryWrap] generates Try*() wrappers for sync, async and void methods.
AutoDispatch.Generator	Compile-time CQRS dispatcher — [Handler] generates a strongly-typed IDispatcher. No IRequest<T>, no reflection.
AutoLog.Generator	Compile-time high-performance logging — [Log(Level, Message)] on a partial method generates LoggerMessage.Define. AOT-safe.
AutoHttpClient.Generator	Compile-time typed HTTP client — [HttpClient] on an interface generates a strongly-typed client. AOT-safe Refit alternative.

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Related Packages

Package	Downloads	Description
AutoWire		Compile-time dependency injection auto-registration for
AutoMap.Generator		Compile-time object mapping for
AutoArchitecture		Compile-time architecture/dependency-rule enforcement for
AutoHttpClient.Generator		Compile-time typed HTTP client generation for
AutoDispatch.Generator		Compile-time CQRS dispatcher for
AutoLog.Generator		Compile-time high-performance logging for
AutoValidate.Generator		Compile-time FluentValidation wiring for

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License

MIT.