Add IDE configs, update Beam version, and enhance RelationalDataProvider

Added JetBrains Rider IDE configuration files and a backup for Beam.Api.csproj. Updated aeqw89.Beam project version to 2.7.0 and package references, including Selenium.WebDriver and System.IO.Hashing. Enhanced RelationalDataProvider to support NextSibling and PreviousSibling relations and configurable traversal distance.

Beam.Dynamic/DataProviders/RelationalDataProvider.cs

@@ -6,11 +6,14 @@ namespace Beam.Dynamic;
 public enum RelationType {
     Parent,
     Child,
+    NextSibling,
+    PreviousSibling,
 }
 
 public class RelationalDataProvider : IComposableDataProvider<HtmlNode?> {
     
     public RelationType RelationType { get; set; } = RelationType.Parent;
+    public int Distance { get; set; } = 1;
     public IBinding? Content { get; set; }
     
     public HtmlNode? Get(HtmlDocument document) {
@@ -23,10 +26,20 @@ public class RelationalDataProvider : IComposableDataProvider<HtmlNode?> {
         return Select(Content?.Select(doc) ?? doc.DocumentNode);
     }
     public HtmlNode? Select(HtmlNode node) {
-        return RelationType switch {
-            RelationType.Parent => node.ParentNode,
-            RelationType.Child => node.FirstChild,
-            _ => throw new NotSupportedException()
-        };
+        return _Select(node, Distance);
+    }
+
+    private HtmlNode? _Select(HtmlNode node, int distance = 0) {
+        while (true) {
+            if (distance == 0) return node;
+            node = RelationType switch {
+                RelationType.Parent => node.ParentNode,
+                RelationType.Child => node.FirstChild,
+                RelationType.NextSibling => node.NextSibling,
+                RelationType.PreviousSibling => node.PreviousSibling,
+                _ => throw new NotSupportedException()
+            };
+            distance = distance - 1;
+        }
     }
 }