From a8fcd127666e6d28e04f02e0a20c7b2d0c0be4ca Mon Sep 17 00:00:00 2001
From: Tim M <49349513+TimothyMakkison@users.noreply.github.com>
Date: Mon, 1 Jul 2024 19:47:04 +0100
Subject: [PATCH] feat: fix form url encoded strings #1593 (#1752)

---
 Refit.Tests/RequestBuilder.cs | 23 +++++++++++++++++++++++
 Refit/FormValueMultimap.cs    |  3 ++-
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/Refit.Tests/RequestBuilder.cs b/Refit.Tests/RequestBuilder.cs
index 5b8f300da..f0477c5aa 100644
--- a/Refit.Tests/RequestBuilder.cs
+++ b/Refit.Tests/RequestBuilder.cs
@@ -3241,6 +3241,29 @@ public void BodyContentGetsUrlEncoded()
             Assert.Equal("Foo=Something&Bar=100&Baz=", output.SendContent);
         }
 
+        [Fact]
+        public void BodyContentGetsUrlEncodedWithCollectionFormat()
+        {
+            var settings = new RefitSettings() { CollectionFormat = CollectionFormat.Csv };
+            var fixture = new RequestBuilderImplementation<IDummyHttpApi>(settings);
+            var factory = fixture.RunRequest("PostSomeUrlEncodedStuff");
+            var output = factory(
+                new object[]
+                {
+                    6,
+                    new
+                    {
+                        Foo = "Something",
+                        Bar = 100,
+                        FooBar = new [] {5,7},
+                        Baz = "" // explicitly use blank to preserve value that would be stripped if null
+                    }
+                }
+            );
+
+            Assert.Equal("Foo=Something&Bar=100&FooBar=5%2C7&Baz=", output.SendContent);
+        }
+
         [Fact]
         public void FormFieldGetsAliased()
         {
diff --git a/Refit/FormValueMultimap.cs b/Refit/FormValueMultimap.cs
index f82114006..291fb3567 100644
--- a/Refit/FormValueMultimap.cs
+++ b/Refit/FormValueMultimap.cs
@@ -65,7 +65,8 @@ public FormValueMultimap(object source, RefitSettings settings)
                     // see if there's a query attribute
                     var attrib = property.GetCustomAttribute<QueryAttribute>(true);
 
-                    if (value is not IEnumerable enumerable)
+                    // add strings/non enumerable properties
+                    if (value is not IEnumerable enumerable || value is string)
                     {
                         Add(
                             fieldName,