SmallToolsIUse.Linq.Extensions

SmallToolsIUse.Linq.Extensions 1.1.0

A set of Linq extension methods which can be used to solve common scenarios in .NET Applications. The package is available on Nuget: https://www.nuget.org/packages/SmallToolsIUse.Linq.Extensions/

In order to use the extension methods, add the following using statement:

using SmallToolsIUse.Linq.Extensions;


IEnumerable Extensions

Check if an instance which implementes IEnumerable is null or empty:

if(!customers.IsNullOrEmpty())
{
 // do something with customers
}

Compare two IEnumerable of different types (e.g. DTO from your API and entities from your database):

var customersToUpdate = customersDto.In(customersFromDb, c => c.Id, c => c.Id)

var customersToDelete = customersFromDb.NotIn(customersDto, c => c.Id, c => c.Id)

var customersToInsert = customersDto.NotIn(customersFromDb, c => c.Id, c => c.Id)

Note: If both collections have the same type, you need to specify a single key selector.

Check if items which exist in both IEnumerable, by key selecor, are different based on a comparrison function:

var modifiedFiles = files.ModifiedIn(filesInBackup, f => f.FileName, (sourceF, destF) => sourceF.ModifiedDate != destF.ModifiedDate)

var modifiedCustomers = customersDto.ModifiedIn(customersFromDb, c => c.Id, c => c.Id, (sourceC, destC) => sourceC.Name != destC.Name)

IQueryable Extensions

Add sorting to your IQueryable using the field name.

Without extensions:

// assume we have sortBy field as a string, as it may be the case if it's captured from the query string.
var myCustomers = dbContext.Customers.Select(c => new CustomerDto());
if(sortBy == "FirstName")
{
  myCustomers = myCustomers.OrderBy(c => c.FirstName); // also, need to check if it's descending or not
}
else if(sortBy == "LastName"
{
  myCustomers = myCustomers.OrderBy(c => c.LastName); // also, need to check if it's descending or not
}

With linq extensions:

// assume we have sortBy field as a string, as it may be the case if it's captured from the query string.
var myCustomers = dbContext.Customers.Select(c => new CustomerDto());
myCustomers = myCustomers.OrderByField(sortBy, orderDirection);

You have the following methods which will be properly translated to SQL:

OrderByField, ThenByField, Paginate, SortAndPaginate