30). Add topic files 87 to 90 (#18259)

* 30). Add topic files 87 to 90

* Apply suggestions from code review

Co-authored-by: Maira Wenzel <[email protected]>

Co-authored-by: Maira Wenzel <[email protected]>

Author: jameshkramer

.openpublishing.redirection.json

@@ -1721,6 +1721,26 @@
       "redirect_url": "/dotnet/standard/linq/find-preceding-siblings",
      "redirect_document_id": true
     },
+    {
+      "source_path": "docs/csharp/programming-guide/concepts/linq/how-to-find-an-attribute-of-the-parent-xpath-linq-to-xml.md",
+      "redirect_url": "/dotnet/standard/linq/find-attribute-parent",
+      "redirect_document_id": true
+    },
+    {
+      "source_path": "docs/csharp/programming-guide/concepts/linq/how-to-find-attributes-of-siblings-with-a-specific-name-xpath-linq-to-xml.md",
+      "redirect_url": "/dotnet/standard/linq/find-attributes-siblings-specific-name",
+      "redirect_document_id": true
+    },
+    {
+      "source_path": "docs/csharp/programming-guide/concepts/linq/how-to-find-elements-with-a-specific-attribute-xpath-linq-to-xml.md",
+      "redirect_url": "/dotnet/standard/linq/find-elements-specific-attribute",
+      "redirect_document_id": true
+    },
+    {
+      "source_path": "docs/csharp/programming-guide/concepts/linq/how-to-find-sibling-nodes-xpath-linq-to-xml.md",
+      "redirect_url": "/dotnet/standard/linq/find-sibling-nodes",
+      "redirect_document_id": true
+    },
     {
       "source_path": "docs/csharp/programming-guide/concepts/threading/how-to-use-a-thread-pool.md",
       "redirect_url": "/dotnet/api/system.threading.threadpool.queueuserworkitem"
@@ -5203,6 +5223,26 @@
       "redirect_url": "/dotnet/standard/linq/find-preceding-siblings",
       "redirect_document_id": false
     },
+    {
+      "source_path": "docs/visual-basic/programming-guide/concepts/linq/how-to-find-an-attribute-of-the-parent-xpath-linq-to-xml.md",
+      "redirect_url": "/dotnet/standard/linq/find-attribute-parent",
+      "redirect_document_id": false
+    },
+    {
+      "source_path": "docs/visual-basic/programming-guide/concepts/linq/how-to-find-attributes-of-siblings-with-a-specific-name.md",
+      "redirect_url": "/dotnet/standard/linq/find-attributes-siblings-specific-name",
+      "redirect_document_id": false
+    },
+    {
+      "source_path": "docs/visual-basic/programming-guide/concepts/linq/how-to-find-elements-with-a-specific-attribute.md",
+      "redirect_url": "/dotnet/standard/linq/find-elements-specific-attribute",
+      "redirect_document_id": false
+    },
+    {
+      "source_path": "docs/visual-basic/programming-guide/concepts/linq/how-to-find-sibling-nodes-xpath-linq-to-xml.md",
+      "redirect_url": "/dotnet/standard/linq/find-sibling-nodes",
+      "redirect_document_id": false
+    },
     {
       "source_path": "docs/visual-basic/programming-guide/concepts/threading/how-to-use-a-thread-pool.md",
       "redirect_url": "/dotnet/api/system.threading.threadpool.queueuserworkitem"

docs/csharp/programming-guide/concepts/linq/how-to-find-an-attribute-of-the-parent-xpath-linq-to-xml.md

@@ -0,0 +1,74 @@
+---
+title: How to find an attribute of the parent - LINQ to XML
+description: "Learn how to navigate to an element and find an attribute of its parent. Two methods are shown: one uses XPathEvaluate, the other uses LINQ to XML query."
+ms.date: 07/20/2015
+dev_langs:
+  - "csharp"
+  - "vb"
+ms.assetid: dbef9d89-a5c4-431f-80cc-7a2ebf323f86
+---
+
+# How to find an attribute of the parent (LINQ to XML)
+
+This article shows how to use <xref:System.Xml.XPath.Extensions.XPathEvaluate%2A> to find an attribute of a parent element, and how to use LINQ to XML query to do the same thing.
+
+## Example: Find the `Author` element, and then find the `id` attribute of its parent
+
+This example first finds an `Author` element in XML document [Sample XML file: Books](sample-xml-file-books.md), and then finds the `id` attribute of its parent element.
+
+The XPath expression is `../@id`.
+
+```csharp
+XDocument books = XDocument.Load("Books.xml");
+
+XElement author =
+    books
+    .Root
+    .Element("Book")
+    .Element("Author");
+
+// LINQ to XML query
+XAttribute att1 =
+    author
+    .Parent
+    .Attribute("id");
+
+// XPath expression
+XAttribute att2 = ((IEnumerable)author.XPathEvaluate("../@id")).Cast<XAttribute>().First();
+
+if (att1 == att2)
+    Console.WriteLine("Results are identical");
+else
+    Console.WriteLine("Results differ");
+Console.WriteLine(att1);
+```
+
+```vb
+Dim books As XDocument = XDocument.Load("Books.xml")
+Dim author As XElement = books.Root.<Book>.<Author>.FirstOrDefault()
+
+' LINQ to XML query
+Dim att1 As XAttribute = author.Parent.Attribute("id")
+
+' XPath expression
+Dim att2 As XAttribute = DirectCast(author.XPathEvaluate("../@id"),  _
+    IEnumerable).Cast(Of XAttribute)().First()
+
+If att1 Is att2 Then
+    Console.WriteLine("Results are identical")
+Else
+    Console.WriteLine("Results differ")
+End If
+Console.WriteLine(att1)
+```
+
+This example produces the following output:
+
+```output
+Results are identical
+id="bk101"
+```
+
+## See also
+
+- [LINQ to XML for XPath Users (Visual Basic)](../../visual-basic/programming-guide/concepts/linq/linq-to-xml-for-xpath-users.md)