QueryKit

You can perform calculations directly within your queries using standard arithmetic operators: +, -, *, /, and % (modulo). These expressions are translated to efficient SQL by Entity Framework.

Examples:

// Find records where Age + Rating is greater than 50
var input = "(Age + Rating) > 50";

// Calculate profit margin and filter
var profitableItems = _dbContext.Products
    .ApplyQueryKitFilter("((Price - Cost) / Price) > 0.2")
    .ToList();

QueryKit allows comparing one property directly to another property on the same entity (or nested properties). This is useful for dynamic filtering where the comparison value is a field rather than a literal.

Examples:

var input = """FirstName == LastName""";

// Compare child property to root property
var input = """Author.Name == Title""";

Property list grouping allows you to apply a single comparison across multiple properties using the syntax (Prop1, Prop2, ...) Operator Value.

Logic Rules:

• Positive Operators (==, @=, _=, ^$, ^^, etc.): Uses OR logic. Matches if the condition is true for at least one property.
• Negative Operators (!=, !@=, !_=, !^$, !^^, etc.): Uses AND logic. Matches only if the condition is true for every property.

Examples:

// Search for "paul" in either FirstName OR LastName
var input = """(FirstName, LastName) @=* \"paul\" """;

// Search for "test" in neither FirstName nor LastName (AND logic)
var input = """(FirstName, LastName) !@=* \"test\" """;

QueryKit can filter into collections.

• Default Behavior: Uses Any logic (matches if any element satisfies the condition).
• All Logic: Prefix the operator with % to use All logic (e.g., %>=).
• Primitive Collections (List<string>, etc.): Use ^$ (Has) or !^$ (Does Not Have).
• Collection Counts: Prefix operators with # (e.g., #>=).

Examples:

// Filter recipes that have an ingredient named "salt"
var input = """Ingredients.Name == \"salt\" """;

// Filter for recipes where all ingredients have stock >= 1
var input = """Ingredients.Stock %>= 1""";

// Filter primitive string collection for "winner"
var input = """Tags ^$ \"winner\" """;

// Get recipes with more than 0 ingredients
var input = """Ingredients #>= 0""";

To use QueryKit in your .NET project, add the NuGet package using the dotnet CLI.

dotnet add package QueryKit

Sorting in QueryKit is performed using a comma-delimited list of properties. You can specify the direction using asc (ascending) or desc (descending). If no direction is specified, asc is the default. You can also use Sieve syntax by prefixing a property with a minus sign (-) to indicate descending order. Spaces after commas are optional.

var input = "Title";
var input = "Title, Age desc";
var input = "Title desc, Age desc";
var input = "Title, Age";
var input = "Title asc, -Age";
var input = "Title, -Age";

QueryKit can be used on in-memory collections (IEnumerable<T>) by using the ApplyQueryKitFilter and ApplyQueryKitSort extension methods. This treats the input string as a parser for expressions against the enumerable items.

var recipeOne = new FakeRecipeBuilder().Build();
var recipeTwo = new FakeRecipeBuilder().Build();
var listOfRecipes = new List<Recipe> { recipeOne, recipeTwo };

var input = $"""{nameof(Recipe.Title)} == \"{recipeOne.Title}\" """ ";

var filteredRecipes = listOfRecipes.ApplyQueryKitFilter(input).ToList();

You can apply string-based filter inputs directly to an IQueryable (such as a DbSet) using the ApplyQueryKitFilter extension method. QueryKit translates the string expression into a LINQ expression automatically.

var filterInput = """FirstName == \"Jane\" && Age > 10""";
var people = _dbContext.People
  	.ApplyQueryKitFilter(filterInput)
  	.ToList();

Sorting can be applied to your query using the ApplyQueryKitSort method. It accepts a comma-separated string of property names and direction indicators (e.g., desc). You can pass a QueryKitConfiguration to handle custom property names during sorting.

var filterInput = """first == \"Jane\" && Age > 10""";
var config = new QueryKitConfiguration(config =>
{
    config.Property<Person>(x => x.FirstName).HasQueryName("first");
});
var people = _dbContext.People
  	.ApplyQueryKitFilter(filterInput, config)
  	.ApplyQueryKitSort("first, Age desc", config)
  	.ToList();