From 6f25663a32a2d3dc38905230094a689a501a8e6d Mon Sep 17 00:00:00 2001
From: Steve Sanderson <SteveSandersonMS@users.noreply.github.com>
Date: Wed, 21 Feb 2018 09:41:57 +0000
Subject: [PATCH] In UriHelper, cache current absolute URL

---
 .../Routing/UriHelper.cs                            | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/Microsoft.AspNetCore.Blazor.Browser/Routing/UriHelper.cs b/src/Microsoft.AspNetCore.Blazor.Browser/Routing/UriHelper.cs
index 430e8138eb..54e6ce9d65 100644
--- a/src/Microsoft.AspNetCore.Blazor.Browser/Routing/UriHelper.cs
+++ b/src/Microsoft.AspNetCore.Blazor.Browser/Routing/UriHelper.cs
@@ -16,6 +16,7 @@ namespace Microsoft.AspNetCore.Blazor.Browser.Routing
     public static class UriHelper
     {
         static readonly string _functionPrefix = typeof(UriHelper).FullName;
+        static string _currentAbsoluteUri;
 
         /// <summary>
         /// An event that fires when the navigation location has changed.
@@ -48,8 +49,13 @@ namespace Microsoft.AspNetCore.Blazor.Browser.Routing
         /// <returns>The browser's current absolute URI.</returns>
         public static string GetAbsoluteUri()
         {
-            return RegisteredFunction.InvokeUnmarshalled<string>(
+            if (_currentAbsoluteUri == null)
+            {
+                _currentAbsoluteUri = RegisteredFunction.InvokeUnmarshalled<string>(
                 $"{_functionPrefix}.getLocationHref");
+            }
+
+            return _currentAbsoluteUri;
         }
 
         /// <summary>
@@ -83,7 +89,10 @@ namespace Microsoft.AspNetCore.Blazor.Browser.Routing
         }
 
         private static void NotifyLocationChanged(string newAbsoluteUri)
-            => OnLocationChanged?.Invoke(null, newAbsoluteUri);
+        {
+            _currentAbsoluteUri = newAbsoluteUri;
+            OnLocationChanged?.Invoke(null, newAbsoluteUri);
+        }
 
         /// <summary>
         /// Given the document's document.baseURI value, returns the URI prefix