Making QueryHelpers.AddQueryString support # in the URL.

src/Microsoft.AspNet.WebUtilities/QueryHelpers.cs

@@ -20,8 +20,8 @@ namespace Microsoft.AspNet.WebUtilities
         /// <returns>The combined result.</returns>
         public static string AddQueryString([NotNull] string uri, [NotNull] string name, [NotNull] string value)
         {
-            bool hasQuery = uri.IndexOf('?') != -1;
+            return AddQueryString(
-            return uri + (hasQuery ? "&" : "?") + UrlEncoder.Default.UrlEncode(name) + "=" + UrlEncoder.Default.UrlEncode(value);
+                uri, new List<KeyValuePair<string, string>> { new KeyValuePair<string, string>(name, value) });
         }
 
         /// <summary>
@@ -29,12 +29,31 @@ namespace Microsoft.AspNet.WebUtilities
         /// </summary>
         /// <param name="uri">The base uri.</param>
         /// <param name="queryString">A collection of name value query pairs to append.</param>
-        /// <returns>The combine result.</returns>
+        /// <returns>The combined result.</returns>
         public static string AddQueryString([NotNull] string uri, [NotNull] IDictionary<string, string> queryString)
         {
+            return AddQueryString(uri, (IEnumerable<KeyValuePair<string, string>>)queryString);
+        }
+
+        private static string AddQueryString(
+            [NotNull] string uri,
+            [NotNull] IEnumerable<KeyValuePair<string, string>> queryString)
+        {
+            var anchorIndex = uri.IndexOf('#');
+            var uriToBeAppended = uri;
+            var anchorText = "";
+            // If there is an anchor, then the query string must be inserted before its first occurance.
+            if (anchorIndex != -1)
+            {
+                anchorText = uri.Substring(anchorIndex);
+                uriToBeAppended = uri.Substring(0, anchorIndex);
+            }
+
+            var queryIndex = uriToBeAppended.IndexOf('?');
+            var hasQuery = queryIndex != -1;
+
             var sb = new StringBuilder();
-            sb.Append(uri);
+            sb.Append(uriToBeAppended);
-            bool hasQuery = uri.IndexOf('?') != -1;
             foreach (var parameter in queryString)
             {
                 sb.Append(hasQuery ? '&' : '?');
@@ -43,6 +62,8 @@ namespace Microsoft.AspNet.WebUtilities
                 sb.Append(UrlEncoder.Default.UrlEncode(parameter.Value));
                 hasQuery = true;
             }
+
+            sb.Append(anchorText);
             return sb.ToString();
         }
 

test/Microsoft.AspNet.WebUtilities.Tests/QueryHelpersTests.cs

@@ -1,7 +1,7 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using System;
+using System.Collections.Generic;
 using System.Linq;
 using Xunit;
 
@@ -52,5 +52,63 @@ namespace Microsoft.AspNet.WebUtilities
             Assert.Equal(1, collection.Count);
             Assert.Equal(new[] { "value1", "" }, collection[""]);
         }
+
+        [Theory]
+        [InlineData("http://contoso.com/", "http://contoso.com/?hello=world")]
+        [InlineData("http://contoso.com/someaction", "http://contoso.com/someaction?hello=world")]
+        [InlineData("http://contoso.com/someaction?q=test", "http://contoso.com/someaction?q=test&hello=world")]
+        [InlineData(
+            "http://contoso.com/someaction?q=test#anchor",
+            "http://contoso.com/someaction?q=test&hello=world#anchor")]
+        [InlineData("http://contoso.com/someaction#anchor", "http://contoso.com/someaction?hello=world#anchor")]
+        [InlineData("http://contoso.com/#anchor", "http://contoso.com/?hello=world#anchor")]
+        [InlineData(
+            "http://contoso.com/someaction?q=test#anchor?value",
+            "http://contoso.com/someaction?q=test&hello=world#anchor?value")]
+        [InlineData(
+            "http://contoso.com/someaction#anchor?stuff",
+            "http://contoso.com/someaction?hello=world#anchor?stuff")]
+        [InlineData(
+            "http://contoso.com/someaction?name?something",
+            "http://contoso.com/someaction?name?something&hello=world")]
+        [InlineData(
+            "http://contoso.com/someaction#name#something",
+            "http://contoso.com/someaction?hello=world#name#something")]
+        public void AddQueryStringWithKeyAndValue(string uri, string expectedUri)
+        {
+            var result = QueryHelpers.AddQueryString(uri, "hello", "world");
+            Assert.Equal(expectedUri, result);
+        }
+
+        [Theory]
+        [InlineData("http://contoso.com/", "http://contoso.com/?hello=world&some=text")]
+        [InlineData("http://contoso.com/someaction", "http://contoso.com/someaction?hello=world&some=text")]
+        [InlineData("http://contoso.com/someaction?q=1", "http://contoso.com/someaction?q=1&hello=world&some=text")]
+        [InlineData("http://contoso.com/some#action", "http://contoso.com/some?hello=world&some=text#action")]
+        [InlineData("http://contoso.com/some?q=1#action", "http://contoso.com/some?q=1&hello=world&some=text#action")]
+        [InlineData("http://contoso.com/#action", "http://contoso.com/?hello=world&some=text#action")]
+        [InlineData(
+            "http://contoso.com/someaction?q=test#anchor?value",
+            "http://contoso.com/someaction?q=test&hello=world&some=text#anchor?value")]
+        [InlineData(
+            "http://contoso.com/someaction#anchor?stuff",
+            "http://contoso.com/someaction?hello=world&some=text#anchor?stuff")]
+        [InlineData(
+            "http://contoso.com/someaction?name?something",
+            "http://contoso.com/someaction?name?something&hello=world&some=text")]
+        [InlineData(
+            "http://contoso.com/someaction#name#something",
+            "http://contoso.com/someaction?hello=world&some=text#name#something")]
+        public void AddQueryStringWithDictionary(string uri, string expectedUri)
+        {
+            var queryStrings = new Dictionary<string, string>()
+                        {
+                            { "hello", "world" },
+                            { "some", "text" }
+                        };
+
+            var result = QueryHelpers.AddQueryString(uri, queryStrings);
+            Assert.Equal(expectedUri, result);
+        }
     }
 }