Add strongly typed overload for OrderBy/ChildOrderBy

Fixes #289

+semver:feature

Author: hazzik

src/FluentNHibernate.Testing/DomainModel/Mapping/OneToManyTester.cs

@@ -946,6 +946,14 @@ public void CanSpecifyOrderByClause()
                 .Element("class/bag").HasAttribute("order-by", "foo");
         }
 
+        [Test]
+        public void CanSpecifyOrderByClauseExpression()
+        {
+            new MappingTester<OneToManyTarget>()
+                .ForMapping(m => m.HasMany(x => x.BagOfChildren).OrderBy(c => c.Name))
+                .Element("class/bag").HasAttribute("order-by", "Name");
+        }
+
         [Test]
         public void OrderByClauseIgnoredForUnorderableCollections()
         {

src/FluentNHibernate/Mapping/ManyToManyPart.cs

@@ -6,6 +6,7 @@
 using FluentNHibernate.MappingModel;
 using FluentNHibernate.MappingModel.Collections;
 using FluentNHibernate.Utils;
+using NHibernate.Criterion;
 
 namespace FluentNHibernate.Mapping
 {
@@ -235,6 +236,17 @@ protected override ICollectionRelationshipMapping GetRelationship()
         /// <summary>
         /// Sets the order-by clause on the collection element.
         /// </summary>
+        public ManyToManyPart<TChild> OrderBy(Expression<Func<TChild, object>> orderBy)
+        {
+            return OrderBy(ExpressionToSql.Convert(orderBy));
+        }
+
+        /// <summary>
+        /// Sets the order-by clause on the collection element.
+        /// </summary>
+        /// <remarks>
+        /// Note: This only supports simple cases, use the string overload for more complex clauses.
+        /// </remarks>
         public ManyToManyPart<TChild> OrderBy(string orderBy)
         {
             collectionAttributes.Set("OrderBy", Layer.UserSupplied, orderBy);
@@ -244,6 +256,17 @@ public ManyToManyPart<TChild> OrderBy(string orderBy)
         /// <summary>
         /// Sets the order-by clause on the many-to-many element.
         /// </summary>
+        public ManyToManyPart<TChild> ChildOrderBy(Expression<Func<TChild, object>> orderBy)
+        {
+            return ChildOrderBy(ExpressionToSql.Convert(orderBy));
+        }
+
+        /// <summary>
+        /// Sets the order-by clause on the many-to-many element.
+        /// </summary>
+        /// <remarks>
+        /// Note: This only supports simple cases, use the string overload for more complex clauses.
+        /// </remarks>
         public ManyToManyPart<TChild> ChildOrderBy(string orderBy)
         {
             relationshipAttributes.Set("OrderBy", Layer.UserSupplied, orderBy);
@@ -335,9 +358,7 @@ public ManyToManyPart<TChild> ChildWhere(string where)
         /// </summary>
         public ManyToManyPart<TChild> ChildWhere(Expression<Func<TChild, bool>> where)
         {
-            var sql = ExpressionToSql.Convert(where);
-
-            return ChildWhere(sql);
+            return ChildWhere(ExpressionToSql.Convert(@where));
         }
 
         protected override CollectionMapping GetCollectionMapping()

src/FluentNHibernate/Mapping/OneToManyPart.cs

@@ -144,6 +144,17 @@ public OneToManyPart<TChild> OrderBy(string orderBy)
             return this;
         }
 
+        /// <summary>
+        /// Sets the order-by clause for this one-to-many relationship.
+        /// </summary>
+        /// <remarks>
+        /// Note: This only supports simple cases, use the string overload for more complex clauses.
+        /// </remarks>
+        public OneToManyPart<TChild> OrderBy(Expression<Func<TChild, object>> orderBy)
+        {
+            return OrderBy(ExpressionToSql.Convert(orderBy));
+        }
+
         /// <summary>
         /// Specify that this collection is read-only
         /// </summary>
@@ -226,13 +237,13 @@ void EnsureGenericDictionary()
 
         /// <summary>
         /// Sets the where clause for this one-to-many relationship.
-        /// Note: This only supports simple cases, use the string overload for more complex clauses.
         /// </summary>
+        /// <remarks>
+        /// Note: This only supports simple cases, use the string overload for more complex clauses.
+        /// </remarks>
         public OneToManyPart<TChild> Where(Expression<Func<TChild, bool>> where)
         {
-            var sql = ExpressionToSql.Convert(where);
-
-            return Where(sql);
+            return Where(ExpressionToSql.Convert(where));
         }
     }
 }