Added Explode and Style to SwaggerParameter

src/Swashbuckle.AspNetCore.Annotations/AnnotationsParameterFilter.cs

@@ -30,7 +30,6 @@ private void ApplyPropertyAnnotations(OpenApiParameter parameter, PropertyInfo p
 
         private void ApplyParamAnnotations(OpenApiParameter parameter, ParameterInfo parameterInfo)
         {
-
             var swaggerParameterAttribute = parameterInfo.GetCustomAttribute<SwaggerParameterAttribute>();
 
             if (swaggerParameterAttribute != null)
@@ -44,6 +43,12 @@ private void ApplySwaggerParameterAttribute(OpenApiParameter parameter, SwaggerP
 
             if (swaggerParameterAttribute.RequiredFlag.HasValue)
                 parameter.Required = swaggerParameterAttribute.RequiredFlag.Value;
+
+            if (swaggerParameterAttribute.ExplodeFlag.HasValue)
+                parameter.Explode = swaggerParameterAttribute.ExplodeFlag.Value;
+
+            if (swaggerParameterAttribute.ParameterStyle.HasValue)
+                parameter.Style = swaggerParameterAttribute.ParameterStyle.Value;
         }
     }
 }

src/Swashbuckle.AspNetCore.Annotations/PublicAPI/PublicAPI.Unshipped.txt

@@ -0,0 +1,4 @@
+Swashbuckle.AspNetCore.Annotations.SwaggerParameterAttribute.Explode.get -> bool
+Swashbuckle.AspNetCore.Annotations.SwaggerParameterAttribute.Explode.set -> void
+Swashbuckle.AspNetCore.Annotations.SwaggerParameterAttribute.Style.get -> string
+Swashbuckle.AspNetCore.Annotations.SwaggerParameterAttribute.Style.set -> void

src/Swashbuckle.AspNetCore.Annotations/SwaggerParameterAttribute.cs

@@ -1,4 +1,6 @@
 using System;
+using Microsoft.OpenApi.Models;
+using Swashbuckle.AspNetCore.SwaggerGen;
 
 namespace Swashbuckle.AspNetCore.Annotations
 {
@@ -30,5 +32,34 @@ public bool Required
         }
 
         internal bool? RequiredFlag { get; set; }
+
+        /// <summary>
+        /// Describes how the parameter value will be serialized based on its type. 
+        /// If not set, default values are for: query - form; path - simple; header - simple; cookie - form.
+        /// </summary>
+        public string Style
+        {
+            get { throw new InvalidOperationException($"Use {nameof(ParameterStyle)} instead"); }
+            set
+            {
+                ParameterStyle = Enum.TryParse(value, ignoreCase: true, out ParameterStyle result) ? result :
+                    throw new NotSupportedException($"'{value}' style is not supported");
+            }
+        }
+
+        internal ParameterStyle? ParameterStyle { get; set; }
+
+        /// <summary>
+        /// When true, array and object parameters are split into separate parameters. This has no 
+        /// effect on other parameter types. 
+        /// The default is true for form style and false for all other styles.
+        /// </summary>
+        public bool Explode
+        {
+            get { throw new InvalidOperationException($"Use {nameof(ExplodeFlag)} instead"); }
+            set { ExplodeFlag = value; }
+        }
+
+        internal bool? ExplodeFlag { get; set; }
     }
-}
+}

test/Swashbuckle.AspNetCore.Annotations.Test/AnnotationsParameterFilterTests.cs

@@ -61,6 +61,43 @@ public void Apply_DoesNotModifyTheRequiredFlag_IfNotSpecifiedWithSwaggerParamete
             Assert.True(parameter.Required);
         }
 
+        [Fact]
+        public void Apply_EnrichesParameterMetadata_IfPropertyDecoratedWithSwaggerParameterAttributeExplode()
+        {
+            var parameter = new OpenApiParameter { };
+            var parameterInfo = typeof(FakeControllerWithSwaggerAnnotations)
+                .GetMethod(nameof(FakeControllerWithSwaggerAnnotations.ActionWithSwaggerParameterAttributeExplode))
+                .GetParameters()[0];
+            var filterContext = new ParameterFilterContext(
+                apiParameterDescription: null,
+                schemaGenerator: null,
+                schemaRepository: null,
+                parameterInfo: parameterInfo);
+
+            Subject().Apply(parameter, filterContext);
+
+            Assert.True(parameter.Explode);
+        }
+
+        [Fact]
+        public void Apply_EnrichesParameterMetadata_IfPropertyDecoratedWithSwaggerParameterAttributeExplodeWithStyle()
+        {
+            var parameter = new OpenApiParameter { };
+            var parameterInfo = typeof(FakeControllerWithSwaggerAnnotations)
+                .GetMethod(nameof(FakeControllerWithSwaggerAnnotations.ActionWithSwaggerParameterAttributeExplodeWithStyle))
+                .GetParameters()[0];
+            var filterContext = new ParameterFilterContext(
+                apiParameterDescription: null,
+                schemaGenerator: null,
+                schemaRepository: null,
+                parameterInfo: parameterInfo);
+
+            Subject().Apply(parameter, filterContext);
+
+            Assert.True(parameter.Explode);
+            Assert.Equal(parameter.Style, ParameterStyle.Form);
+        }
+
         private AnnotationsParameterFilter Subject()
         {
             return new AnnotationsParameterFilter();

test/Swashbuckle.AspNetCore.Annotations.Test/AnnotationsRequestBodyFilterTests.cs

@@ -72,7 +72,7 @@ public void Apply_DoesNotModifyTheRequiredFlag_IfNotSpecifiedWithSwaggerParamete
 
             var requestBody = new OpenApiRequestBody { Required = true };
             var parameterInfo = typeof(FakeControllerWithSwaggerAnnotations)
-                .GetMethod(nameof(FakeControllerWithSwaggerAnnotations.ActionWithSwaggerRequestbodyAttributeDescriptionOnly))
+                .GetMethod(nameof(FakeControllerWithSwaggerAnnotations.ActionWithSwaggerRequestBodyAttributeDescriptionOnly))
                 .GetParameters()[0];
             var bodyParameterDescription = new ApiParameterDescription
             {

test/Swashbuckle.AspNetCore.Annotations.Test/Fixtures/FakeControllerWithSwaggerAnnotations.cs

@@ -25,6 +25,14 @@ public void ActionWithSwaggerParameterAttributeDescriptionOnly(
             [SwaggerParameter("Description for param")] string param)
         { }
 
+        public void ActionWithSwaggerParameterAttributeExplode(
+            [SwaggerParameter("Description for param", Explode = true)] List<string> param)
+        { }
+
+        public void ActionWithSwaggerParameterAttributeExplodeWithStyle(
+            [SwaggerParameter("Description for param", Explode = true, Style = "form")] List<string> param)
+        { }
+
         public void ActionWithSwaggerSchemaAttribute(
             [SwaggerSchema("Description for param", Format = "date")] string param)
         { }
@@ -33,7 +41,7 @@ public void ActionWithSwaggerRequestBodyAttribute(
             [SwaggerRequestBody("Description for param", Required = true)] string param)
         { }
 
-        public void ActionWithSwaggerRequestbodyAttributeDescriptionOnly(
+        public void ActionWithSwaggerRequestBodyAttributeDescriptionOnly(
             [SwaggerRequestBody("Description for param")] string param)
         { }