Extensão para metodo ApllySort

CourseLibrary.API/Helpers/IQueryableExtensions.cs

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+using CourseLibrary.API.Services;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Linq.Dynamic.Core;
+using System.Threading.Tasks;
+namespace CourseLibrary.API.Helpers
+{
+ public static class IQueryableExtensions
+ {
+ public static IQueryable<T> ApplySort<T>(this IQueryable<T> source, string orderBy,
+ Dictionary<string, PropertyMappingValue> mappingDictionary)
+ {
+ if (source == null)
+ {
+ throw new ArgumentNullException(nameof(source));
+ }
+
+ if (mappingDictionary == null)
+ {
+ throw new ArgumentNullException(nameof(mappingDictionary));
+ }
+
+ if (string.IsNullOrWhiteSpace(orderBy))
+ {
+ return source;
+ }
+
+ var orderByString = string.Empty;
+
+ // the orderBy string is separated by ",", so we split it.
+ var orderByAfterSplit = orderBy.Split(',');
+
+ // apply each orderby clause 
+ foreach (var orderByClause in orderByAfterSplit)
+ {
+ // trim the orderBy clause, as it might contain leading
+ // or trailing spaces. Can't trim the var in foreach,
+ // so use another var.
+ var trimmedOrderByClause = orderByClause.Trim();
+
+ // if the sort option ends with with " desc", we order
+ // descending, ortherwise ascending
+ var orderDescending = trimmedOrderByClause.EndsWith(" desc");
+
+ // remove " asc" or " desc" from the orderBy clause, so we 
+ // get the property name to look for in the mapping dictionary
+ var indexOfFirstSpace = trimmedOrderByClause.IndexOf(" ");
+ var propertyName = indexOfFirstSpace == -1 ?
+ trimmedOrderByClause : trimmedOrderByClause.Remove(indexOfFirstSpace);
+
+ // find the matching property
+ if (!mappingDictionary.ContainsKey(propertyName))
+ {
+ throw new ArgumentException($"Key mapping for {propertyName} is missing");
+ }
+
+ // get the PropertyMappingValue
+ var propertyMappingValue = mappingDictionary[propertyName];
+
+ if (propertyMappingValue == null)
+ {
+ throw new ArgumentNullException("propertyMappingValue");
+ }
+
+ // Run through the property names 
+ // so the orderby clauses are applied in the correct order
+ foreach (var destinationProperty in
+ propertyMappingValue.DestinationProperties)
+ {
+ // revert sort order if necessary
+ if (propertyMappingValue.Revert)
+ {
+ orderDescending = !orderDescending;
+ }
+
+ orderByString = orderByString +
+ (string.IsNullOrWhiteSpace(orderByString) ? string.Empty : ", ")
+ + destinationProperty
+ + (orderDescending ? " descending" : " ascending");
+ }
+ }
+
+ return source.OrderBy(orderByString);
+ }
+ }
+}