先上对比图 图一无法选择文件，图二可以选择文件

图一

图二

添加过滤器

public class SwaggerFileUploadFilter : IOperationFilter
{

    /// <summary>  
    /// swagger过滤器（此处的Apply会被swagger的每个接口都调用生成文档说明，所以在此处可以对每一个接口进行过滤操作）  
    /// </summary>  
    /// <param name="operation"></param>  
    /// <param name="context"></param>  
    public void Apply(Operation operation, OperationFilterContext context)  
    {  
        if (!context.ApiDescription.HttpMethod.Equals("POST", StringComparison.OrdinalIgnoreCase) &&  
        !context.ApiDescription.HttpMethod.Equals("PUT", StringComparison.OrdinalIgnoreCase))  
        {  
            return;  
        }  
        var apiDescription = context.ApiDescription;  
        var parameters = context.ApiDescription.ParameterDescriptions.Where(n => n.Type == typeof(IFormFileCollection) || n.Type == typeof(IFormFile)).ToList();//parameterDescriptions包含了每个接口所带所有参数信息  
        if (parameters.Count() <= 0)  
        {  
            return;  
        }  
        operation.Consumes.Add("multipart/form-data");  
        foreach (var fileParameter in parameters)  
        {  
            var parameter = operation.Parameters.Single(n => n.Name == fileParameter.Name);  
            operation.Parameters.Remove(parameter);  
            operation.Parameters.Add(new NonBodyParameter  
            {  
                Name = parameter.Name,  
                In = "formData",  
                Description = parameter.Description,  
                Required = parameter.Required,  
                Type = "file",  
                CollectionFormat = "multi"  
            });  
        }  
    }  
}

　　注册swagger服务

创建方法