32943-Sugar for HierarchyId path generation

src/EFCore.SqlServer.Abstractions/HierarchyId.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Diagnostics.CodeAnalysis;
+using System.Text;
 using System.Text.Json.Serialization;
 using Microsoft.EntityFrameworkCore.Internal;
 using Microsoft.SqlServer.Types;
@@ -25,14 +26,24 @@ public HierarchyId()
     }
 
     /// <summary>
-    ///     Initializes a new instance of the<see cref="HierarchyId" /> class. Equivalent to <see cref="Parse" />.
+    ///     Initializes a new instance of the<see cref="HierarchyId" /> class. Equivalent to <see cref="Parse(string?)" />.
     /// </summary>
     /// <param name="value">The string representation of the node.</param>
     public HierarchyId(string value)
         : this(SqlHierarchyId.Parse(value))
     {
     }
 
+    /// <summary>
+    ///     Initializes a new instance of the<see cref="HierarchyId" /> class. Equivalent to <see cref="Parse(HierarchyId, IReadOnlyList{int})" />.
+    /// </summary>
+    /// <param name="parentHierarchyId">The parent HierarchyId of node.</param>
+    /// <param name="parentId">The parent Id of current node. It can be more than one element if want have path like: "/1/2/3.1/", otherwise one element for have path like: "/1/2/3/".</param>
+    public HierarchyId(HierarchyId parentHierarchyId, IReadOnlyList<int> parentId)
+        : this(Parse(parentHierarchyId,parentId))
+    {
+    }
+
     /// <summary>
     ///     Initializes a new instance of the<see cref="HierarchyId" /> class.
     /// </summary>
@@ -63,6 +74,33 @@ public static HierarchyId GetRoot()
     public static HierarchyId? Parse(string? input)
         => (HierarchyId?)SqlHierarchyId.Parse(input);
 
+    /// <summary>
+    /// Converts the <paramref name= "parentHierarchyId" /> and <paramref name= "parentId" /> of a node to a <see cref="HierarchyId" /> value.
+    /// </summary>
+    /// <param name="parentHierarchyId">The parent HierarchyId of node.</param>
+    /// <param name="parentId">The parent Id of current node. It can be more than one element if want have path like: "/1/2/3.1/", otherwise one element for have path like: "/1/2/3/".</param>
+    /// <returns>A <see cref="HierarchyId" /> value.</returns>
+    [return: NotNullIfNotNull(nameof(parentHierarchyId))]
+    [return: NotNullIfNotNull(nameof(parentId))]
+    public static HierarchyId? Parse(HierarchyId parentHierarchyId , IReadOnlyList<int> parentId)
+        => GenerateHierarchyIdBasedOnParent(parentHierarchyId, parentId);
+
+    //This Method can move to "SqlHierarchyId in Microsoft.SqlServer.Types", if we don't want put it in this abstraction.
+    private static HierarchyId GenerateHierarchyIdBasedOnParent(HierarchyId parent, IReadOnlyList<int> parentId)
+    {
+        if (parent is null)
+            return HierarchyId.GetRoot();
+
+        if (parentId.Count < 1)
+            return parent;
+
+        var specificPath = new StringBuilder(parent.ToString());
+        specificPath.Append(string.Join(".", parentId));
+        specificPath.Append('/');
+
+        return HierarchyId.Parse(specificPath.ToString());
+    }
+
     /// <inheritdoc />
     public virtual int CompareTo(HierarchyId? other)
         => _value.CompareTo((SqlHierarchyId)other);

test/EFCore.SqlServer.HierarchyId.Tests/WrapperTests.cs

@@ -35,4 +35,30 @@ public void GetReparentedValue_returns_null_when_newRoot_is_null()
     [ConditionalFact]
     public void IsDescendantOf_returns_false_when_parent_is_null()
         => Assert.False(HierarchyId.Parse("/1/").IsDescendantOf(null));
+
+    [ConditionalFact]
+    public void Parse_overloads_works_when_parentId_is_simpleId()
+        => Assert.Equal(HierarchyId.Parse(_parent, parentId: [2]), HierarchyId.Parse("/1/2/"));
+
+    [ConditionalFact]
+    public void Parse_overloads_works_when_parentId_is_dottedString()
+        => Assert.Equal(HierarchyId.Parse(_parent, parentId: [2,1]), HierarchyId.Parse("/1/2.1/"));
+
+    [ConditionalFact]
+    public void Parse_overloads_works_when_parentId_is_empty()
+        => Assert.Equal(HierarchyId.Parse(_parent, parentId: []), HierarchyId.Parse("/1/"));
+
+    [ConditionalFact]
+    public void Parse_overloads_works_when_parentHierarchy_is_root_and_parentId_is_simple()
+        => Assert.Equal(HierarchyId.Parse(HierarchyId.GetRoot(), parentId: [1]), HierarchyId.Parse("/1/"));
+
+    [ConditionalFact]
+    public void Parse_overloads_works_when_parentHierarchy_is_root_and_parentId_is_empty()
+        => Assert.Equal(HierarchyId.Parse(HierarchyId.GetRoot(), parentId: []), HierarchyId.Parse("/"));
+
+    [ConditionalFact]
+    public void Parse_overloads_works_when_parentHierarchy_is_null_and_parentId_is_empty()
+        => Assert.Equal(HierarchyId.Parse(null, parentId: []), HierarchyId.Parse("/"));
+
+    private readonly HierarchyId _parent = HierarchyId.Parse("/1/");
 }