Use DeepObject parameter style for dictionary

src/Swashbuckle.AspNetCore.SwaggerGen/SchemaGenerator/SchemaGenerator.cs

@@ -367,15 +367,13 @@ private OpenApiSchema CreateDictionarySchema(DataContract dataContract, SchemaRe
                     AdditionalPropertiesAllowed = false
                 };
             }
-            else
+
+            return new OpenApiSchema
             {
-                return new OpenApiSchema
-                {
-                    Type = "object",
-                    AdditionalPropertiesAllowed = true,
-                    AdditionalProperties = GenerateSchema(dataContract.DictionaryValueType, schemaRepository)
-                };
-            }
+                Type = "object",
+                AdditionalPropertiesAllowed = true,
+                AdditionalProperties = GenerateSchema(dataContract.DictionaryValueType, schemaRepository)
+            };
         }
 
         private OpenApiSchema CreateObjectSchema(DataContract dataContract, SchemaRepository schemaRepository)

src/Swashbuckle.AspNetCore.SwaggerGen/SwaggerGenerator/SwaggerGenerator.cs

@@ -602,10 +602,19 @@ private OpenApiParameter GenerateParameterWithoutFilter(
                 In = location,
                 Required = isRequired,
                 Schema = schema,
-                Description = description
+                Description = description,
+                Style = GetParameterStyle(type, apiParameter.Source)
             };
         }
 
+        private static ParameterStyle? GetParameterStyle(Type type, BindingSource source)
+        {
+            return source == BindingSource.Query && type.IsGenericType &&
+                   typeof(IEnumerable<KeyValuePair<string, string>>).IsAssignableFrom(type)
+                ? ParameterStyle.DeepObject
+                : null;
+        }
+
         private (OpenApiParameter, ParameterFilterContext) GenerateParameterAndContext(
             ApiParameterDescription apiParameter,
             SchemaRepository schemaRepository)

test/Swashbuckle.AspNetCore.IntegrationTests/SwaggerVerifyIntegrationTest.SwaggerEndpoint_ReturnsValidSwaggerJson_DotNet6_startupType=Basic.Startup_swaggerRequestUri=v1.verified.txt

@@ -837,6 +837,18 @@
                 "type": "string"
               }
             }
+          },
+          {
+            "name": "search",
+            "in": "query",
+            "required": true,
+            "style": "deepObject",
+            "schema": {
+              "type": "object",
+              "additionalProperties": {
+                "type": "string"
+              }
+            }
           }
         ],
         "responses": {

test/Swashbuckle.AspNetCore.IntegrationTests/SwaggerVerifyIntegrationTest.SwaggerEndpoint_ReturnsValidSwaggerJson_startupType=Basic.Startup_swaggerRequestUri=v1.verified.txt

@@ -837,6 +837,18 @@
                 "type": "string"
               }
             }
+          },
+          {
+            "name": "search",
+            "in": "query",
+            "required": true,
+            "style": "deepObject",
+            "schema": {
+              "type": "object",
+              "additionalProperties": {
+                "type": "string"
+              }
+            }
           }
         ],
         "responses": {

test/WebSites/Basic/Controllers/FromQueryParamsController.cs

@@ -15,7 +15,7 @@ public IActionResult ValidateAddress([FromQuery]Address address)
         }
 
         [HttpGet("zip-codes/validate")]
-        public IActionResult ValidateZipCodes([FromQuery]IEnumerable<string> zipCodes)
+        public IActionResult ValidateZipCodes([FromQuery]IEnumerable<string> zipCodes, [FromQuery(Name = "search")] [Required] Dictionary<string, string> parameters)
         {
             return new NoContentResult(); 
         }