Fixes #1286: String Collections support in $select.

src/Microsoft.AspNetCore.OData/Common/TypeHelper.cs

@@ -252,6 +252,26 @@ Type collectionInterface
             return false;
         }
 
+        /// <summary>
+        /// Check whether the given type is a primitive type or known type.
+        /// </summary>
+        /// <param name="type">The type to validate.</param>
+        /// <returns>True if type is primitive or known type, otherwise False.</returns>
+        public static bool IsPrimitiveOrKnownType(Type type)
+        {
+            return type.IsPrimitive 
+                   || type == typeof(string)
+                   || type == typeof(Uri)
+                   || type == typeof(DateTime)
+#if NET6_0_OR_GREATER
+        || type == typeof(DateOnly)
+        || type == typeof(TimeOnly)
+#endif
+                   || type == typeof(DateTimeOffset)
+                   || type == typeof(Guid)
+                   || type == typeof(Decimal);
+        }
+
         internal static bool IsDictionary(Type clrType)
         {
             if (clrType == null)

src/Microsoft.AspNetCore.OData/Microsoft.AspNetCore.OData.xml

@@ -1181,6 +1181,13 @@
             <param name="elementType">out: the element type of the collection.</param>
             <returns>True if the type is an enumeration; false otherwise.</returns>
         </member>
+        <member name="M:Microsoft.AspNetCore.OData.Common.TypeHelper.IsPrimitiveOrKnownType(System.Type)">
+            <summary>
+            Check whether the given type is a primitive type or known type.
+            </summary>
+            <param name="type">The type to validate.</param>
+            <returns>True if type is primitive or known type, otherwise False.</returns>
+        </member>
         <member name="M:Microsoft.AspNetCore.OData.Common.TypeHelper.GetImplementedIEnumerableType(System.Type)">
             <summary>
             Returns type of T if the type implements IEnumerable of T, otherwise, return null.

src/Microsoft.AspNetCore.OData/Query/Expressions/SelectExpandBinder.cs

@@ -1357,7 +1357,9 @@ private Expression ProjectCollection(QueryBinderContext context, Expression sour
             // expression
             //      source.Select((ElementType element) => new Wrapper { })
             var selectMethod = GetSelectMethod(elementType, projection.Type);
-            Expression selectedExpresion = Expression.Call(selectMethod, source, selector);
+            bool isPrimitiveCollection = TypeHelper.IsPrimitiveOrKnownType(elementType);
+            Expression selectedExpresion =
+                isPrimitiveCollection ? source : Expression.Call(selectMethod, source, selector);
 
             // Append ToList() to collection as a hint to LINQ provider to buffer correlated sub-queries in memory and avoid executing N+1 queries
             if (settings.EnableCorrelatedSubqueryBuffering)

test/Microsoft.AspNetCore.OData.E2E.Tests/Lists/ListsContext.cs

@@ -0,0 +1,26 @@
+//-----------------------------------------------------------------------------
+// <copyright file="ListsContext.cs" company=".NET Foundation">
+//      Copyright (c) .NET Foundation and Contributors. All rights reserved.
+//      See License.txt in the project root for license information.
+// </copyright>
+//------------------------------------------------------------------------------
+
+using System;
+using System.IO;
+using Microsoft.EntityFrameworkCore;
+
+namespace Microsoft.AspNetCore.OData.E2E.Tests.Lists
+{
+    public class ListsContext : DbContext
+    {
+        public ListsContext(DbContextOptions<ListsContext> options)
+            : base(options)
+        {
+
+        }
+
+        public DbSet<Product> Products{ get; set; }
+        public DbSet<Order> Orders{ get; set; }
+    }
+}
+

test/Microsoft.AspNetCore.OData.E2E.Tests/Lists/ListsController.cs

@@ -0,0 +1,186 @@
+//-----------------------------------------------------------------------------
+// <copyright file="ListsController.cs" company=".NET Foundation">
+//      Copyright (c) .NET Foundation and Contributors. All rights reserved.
+//      See License.txt in the project root for license information.
+// </copyright>
+//------------------------------------------------------------------------------
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.OData.Deltas;
+using Microsoft.AspNetCore.OData.Formatter;
+using Microsoft.AspNetCore.OData.Query;
+using Microsoft.AspNetCore.OData.Routing.Attributes;
+using Microsoft.AspNetCore.OData.Routing.Controllers;
+using Microsoft.EntityFrameworkCore;
+using Xunit;
+
+namespace Microsoft.AspNetCore.OData.E2E.Tests.Lists
+{
+    [Route("convention")]
+    public class ProductsController : ODataController
+    {
+        private readonly ListsContext _dbContext;
+        public ProductsController(ListsContext context)
+        {
+            _dbContext = context;
+        }
+
+        [EnableQuery(PageSize = 10, MaxExpansionDepth = 5)]
+        public IActionResult Get()
+        {
+            return Ok(_dbContext.Products);
+        }
+
+        [EnableQuery]
+        public IActionResult Get(string key)
+        {
+            return Ok(_dbContext.Products.Find(key));
+        }
+
+        public IActionResult Post([FromBody] Product Product)
+        {
+            Product.ProductId = _dbContext.Products.Count() + 1+"";
+            _dbContext.Products.Add(Product);
+            _dbContext.SaveChanges();
+
+            return Created(Product);
+        }
+
+        public IActionResult Put(int key, [FromBody] Product Product)
+        {
+            Product.ProductId = key+"";
+            Product originalProduct = _dbContext.Products.Find(key);
+
+            if (originalProduct == null)
+            {
+                _dbContext.Products.Add(Product);
+
+                return Created(Product);
+            }
+
+            _dbContext.Products.Remove(originalProduct);
+            _dbContext.Products.Add(Product);
+            return Ok(Product);
+        }
+
+        public IActionResult Patch(int key, [FromBody] Delta<Product> delta)
+        {
+            Product originalProduct = _dbContext.Products.Find(key);
+
+            if (originalProduct == null)
+            {
+                Product temp = new Product();
+                delta.Patch(temp);
+                _dbContext.Products.Add(temp);
+                return Created(temp);
+            }
+
+            delta.Patch(originalProduct);
+            return Ok(delta);
+        }
+
+        public IActionResult Delete(int key)
+        {
+            Product Product = _dbContext.Products.Find(key);
+
+            _dbContext.Products.Remove(Product);
+            return this.StatusCode(StatusCodes.Status204NoContent);
+        }
+
+        [HttpPost("ResetDataSource")]
+        public IActionResult ResetDataSource()
+        {
+            _dbContext.Orders.RemoveRange(_dbContext.Orders);
+            _dbContext.Products.RemoveRange(_dbContext.Products);
+            _dbContext.SaveChanges();
+
+            // Add new seed data
+            _dbContext.Products.AddRange(
+               new Product
+               {
+                   ProductId = "1",
+                   Name = "Product1",
+                   Category = "Category1",
+                   ListTestString = new List<string> { "Test1", "Test2", "Test99" },
+                   ListTestBool = new List<bool> { true, false },
+                   ListTestInt = new List<int> { 1, 2, 3 },
+                   ListTestDouble = new List<double> { 1.1, 2.2 },
+                   ListTestFloat = new List<float> { 1.1f, 2.2f },
+                   ListTestDateTime = new List<DateTimeOffset> { DateTime.Now, DateTime.UtcNow },
+                   ListTestUri = new List<Uri> { new Uri("https://example.com") },
+                   ListTestUint = new uint[] { 1, 2, 3 },
+                   ListTestOrder = new List<Order>
+                    {
+                        new Order { OrderId = "Order1" },
+                        new Order { OrderId = "Order2" }
+                    }
+               },
+                new Product
+                {
+                    ProductId = "2",
+                    Name = "Product2",
+                    Category = "Category2",
+                    ListTestString = new List<string> { "Test3", "Test4", "Test99" },
+                    ListTestBool = new List<bool> { false, true },
+                    ListTestInt = new List<int> { 4, 5, 6 },
+                    ListTestDouble = new List<double> { 3.3, 4.4 },
+                    ListTestFloat = new List<float> { 3.3f, 4.4f },
+                    ListTestDateTime = new List<DateTimeOffset> { DateTime.Now.AddDays(1), DateTime.UtcNow.AddDays(1) },
+                    ListTestUri = new List<Uri> { new Uri("https://example.org") },
+                    ListTestUint = new uint[] { 4, 5, 6 }
+                },
+                new Product
+                {
+                    ProductId = "3",
+                    Name = "Product3",
+                    Category = "Category3",
+                    ListTestString = new List<string> { "Test5", "Test6" },
+                    ListTestBool = new List<bool> { true, true },
+                    ListTestInt = new List<int> { 7, 8, 9 },
+                    ListTestDouble = new List<double> { 5.5, 6.6 },
+                    ListTestFloat = new List<float> { 5.5f, 6.6f },
+                    ListTestDateTime = new List<DateTimeOffset> { DateTime.Now.AddDays(2), DateTime.UtcNow.AddDays(2) },
+                    ListTestUri = new List<Uri> { new Uri("https://example.net") },
+                    ListTestUint = new uint[] { 7, 8, 9 }
+                },
+                new Product
+                {
+                    ProductId = "4",
+                    Name = "Product4",
+                    Category = "Category4",
+                    ListTestString = new List<string> { "Test98", "Test98" },
+                    ListTestBool = new List<bool> { false, false },
+                    ListTestInt = new List<int> { 10, 11, 12 },
+                    ListTestDouble = new List<double> { 7.7, 8.8 },
+                    ListTestFloat = new List<float> { 7.7f, 8.8f },
+                    ListTestDateTime = new List<DateTimeOffset> { DateTime.Now.AddDays(3), DateTime.UtcNow.AddDays(3) },
+                    ListTestUri = new List<Uri> { new Uri("https://example.edu") },
+                    ListTestUint = new uint[] { 10, 11, 12 }
+                },
+                new Product
+                {
+                    ProductId = "5",
+                    Name = "Product5",
+                    Category = "Category5",
+                    ListTestString = new List<string> { "Test98", "Test98" },
+                    ListTestBool = new List<bool> { true, false },
+                    ListTestInt = new List<int> { 13, 14, 15 },
+                    ListTestDouble = new List<double> { 9.9, 10.10 },
+                    ListTestFloat = new List<float> { 9.9f, 10.10f },
+                    ListTestDateTime = new List<DateTimeOffset> { DateTime.Now.AddDays(4), DateTime.UtcNow.AddDays(4) },
+                    ListTestUri = new List<Uri> { new Uri("https://example.gov") },
+                    ListTestUint = new uint[] { 13, 14, 15 }
+                }
+            );
+            _dbContext.SaveChanges();
+            return this.StatusCode(StatusCodes.Status204NoContent);
+        }
+
+
+    }
+
+}

test/Microsoft.AspNetCore.OData.E2E.Tests/Lists/ListsDataModel.cs

@@ -0,0 +1,36 @@
+//-----------------------------------------------------------------------------
+// <copyright file="ListsDataModel.cs" company=".NET Foundation">
+//      Copyright (c) .NET Foundation and Contributors. All rights reserved.
+//      See License.txt in the project root for license information.
+// </copyright>
+//------------------------------------------------------------------------------
+
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+using System.Runtime.Serialization;
+
+namespace Microsoft.AspNetCore.OData.E2E.Tests.Lists
+{
+    public class Product
+    {
+        [Key]
+        public string ProductId { get; set; }
+        public string Name { get; set; }
+        public string Category { get; set; }
+        public IList<string> ListTestString { get; set; } = new List<string>();
+        public IList<bool> ListTestBool { get; set; }
+        public IList<int> ListTestInt { get; set; }
+        public IList<double> ListTestDouble { get; set; }
+        public IList<float> ListTestFloat { get; set; }
+        public IList<DateTimeOffset> ListTestDateTime { get; set; }
+        public IList<Uri> ListTestUri { get; set; }
+        public uint[] ListTestUint { get; set; }
+        public IList<Order>? ListTestOrder { get; set; }
+    }
+
+    public class Order
+    {
+        [Key] public string OrderId { get; set; }
+    }
+}

test/Microsoft.AspNetCore.OData.E2E.Tests/Lists/ListsEdmModel.cs

@@ -0,0 +1,28 @@
+//-----------------------------------------------------------------------------
+// <copyright file="ListsEdmModel.cs" company=".NET Foundation">
+//      Copyright (c) .NET Foundation and Contributors. All rights reserved.
+//      See License.txt in the project root for license information.
+// </copyright>
+//------------------------------------------------------------------------------
+
+using Microsoft.OData.Edm;
+using Microsoft.OData.ModelBuilder;
+
+namespace Microsoft.AspNetCore.OData.E2E.Tests.Lists
+{
+    internal class ListsEdmModel
+    {
+        public static IEdmModel GetConventionModel()
+        {
+            ODataConventionModelBuilder builder = new ODataConventionModelBuilder();
+            EntitySetConfiguration<Product> Products = builder.EntitySet<Product>("Products");
+            EntitySetConfiguration<Order> Orders = builder.EntitySet<Order>("Orders");
+
+            builder.Namespace = typeof(Product).Namespace;
+            builder.Namespace = typeof(Order).Namespace;
+
+            var edmModel = builder.GetEdmModel();
+            return edmModel;
+        }
+    }
+}