Tolitech.Queryable.Extensions 1.0.0-preview.3

Tolitech.Queryable.Extensions

The Tolitech.Queryable.Extensions library provides utility methods to simplify querying operations on IQueryable data sources. It includes features for dynamic ordering and pagination, enabling efficient data retrieval and manipulation in LINQ queries.

Features

1. Dynamic Ordering

• Allows sorting IQueryable collections dynamically based on property names specified in a string.
• Supports multi-level sorting with multiple fields and ascending/descending order.

2. Pagination

• Provides an easy way to implement paging logic with parameters for page number and page size.

Usage

1. Dynamic Ordering with OrderByExpression

Use the OrderByExpression method to dynamically sort an IQueryable collection based on a string that specifies the property and order.

Syntax

public static IQueryable<T> OrderByExpression<T>(
    this IQueryable<T> query, 
    string orderByString
)

• query: The data source to sort.
• orderByString: A comma-separated string specifying the sorting criteria. Use : to indicate sorting order (asc or desc). Default is asc.

Example

using Tolitech.Queryable.Extensions;

// Sample data
var products = new List<Product>
{
    new Product { Id = 1, Name = "Apple", Price = 10 },
    new Product { Id = 2, Name = "Orange", Price = 8 },
    new Product { Id = 3, Name = "Banana", Price = 5 }
}.AsQueryable();

// Order by Name (ascending) and then Price (descending)
string orderByString = "Name,Price:desc";

var sortedProducts = products.OrderByExpression(orderByString);

foreach (var product in sortedProducts)
{
    Console.WriteLine($"{product.Name} - {product.Price}");
}

Output

Apple - 10
Banana - 5
Orange - 8

2. Pagination with Paginate

Use the Paginate method to retrieve a specific page of items from an IQueryable collection.

Syntax

public static IQueryable<T> Paginate<T>(
    this IQueryable<T> source, 
    int pageNumber, 
    int pageSize
)

• source: The data source to paginate.
• pageNumber: The page number to retrieve (starting at 1).
• pageSize: The number of items per page.

Example

using Tolitech.Queryable.Extensions;

// Sample data
var products = new List<Product>
{
    new Product { Id = 1, Name = "Apple", Price = 10 },
    new Product { Id = 2, Name = "Orange", Price = 8 },
    new Product { Id = 3, Name = "Banana", Price = 5 },
    new Product { Id = 4, Name = "Grapes", Price = 15 },
    new Product { Id = 5, Name = "Pineapple", Price = 20 }
}.AsQueryable();

// Paginate data: Page 2, 2 items per page
int pageNumber = 2;
int pageSize = 2;

var paginatedProducts = products.Paginate(pageNumber, pageSize);

foreach (var product in paginatedProducts)
{
    Console.WriteLine($"{product.Name} - {product.Price}");
}

Output

Banana - 5
Grapes - 15

API Reference

1. OrderByExpression

• Dynamically sorts the IQueryable based on the specified string.
• Supports multi-level sorting using a comma-separated list.
• Default sorting order is ascending (asc).

Example Input Strings:

• "Name": Sorts by Name ascending.
• "Price:desc": Sorts by Price descending.
• "Category,Price:desc": Sorts by Category ascending, then by Price descending.

2. Paginate

• Implements paging logic for IQueryable data sources.
• Skips records based on pageNumber and retrieves pageSize number of items.

Example Parameters:

• pageNumber = 1, pageSize = 5: Returns the first 5 items.
• pageNumber = 2, pageSize = 3: Skips the first 3 items and returns the next 3 items.