Enable file upload button on Swagger's page.

FileUploadOperation.cs

using Swashbuckle.Swagger;
using System;
using System.Web.Http.Description;

namespace UploadingFileFromSwagger.Models
{
    /* How to use:  
            GlobalConfiguration.Configuration
                .EnableSwagger(c => 
                {
                      c.OperationFilter<FileUploadOperation>();
                });
     */

    public class FileUploadOperation : IOperationFilter
    {
        public void Apply(Operation operation, SchemaRegistry schemaRegistry, ApiDescription apiDescription)
        {
            if (StringComparer.OrdinalIgnoreCase.Equals(operation.operationId, "Values_Post")) // The format is Action_Method.
            {
                operation.parameters.Clear();
                operation.parameters.Add(new Parameter
                {
                    name = "uploadedFile1",
                    @in = "formData",
                    description = "Upload File 1",
                    required = true,
                    type = "file"
                });
                operation.parameters.Add(new Parameter
                {
                    name = "uploadedFile2",
                    @in = "formData",
                    description = "Upload File 2",
                    required = true,
                    type = "file"
                });
                operation.consumes.Add("multipart/form-data");
            }
        }
    }
}