使用JSON asp.net核心api上传多部分/表单数据图像

本文介绍了使用JSON asp核心api上传多部分/表单数据图像的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

在单个POST中同时发布图像和JSON的最佳方法是什么? (使用多部分) 我有一个表单，其中包含一些放入JSON的数据，用户可以添加0到6张照片并将其提交给API.

What's the best way to POST both images and JSON at the same time in a single POST ? (using multipart) I have a form with some data that i put into JSON and the users can add 0 to 6 photos and submit it to the API.

有人可以解释我该怎么做吗?

Can someone explain me how to do it ?

这是我的代码，感谢您的帮助:

Edit : Here is my code thanks to your help :

// POST api/<controller> [HttpPost, Authorize(AuthenticationSchemes = JwtBearerDefaults.AuthenticationScheme)] public IActionResult Post(ViewModel vm) { IActionResult response = Unauthorized(); var data = vm.FamilleProduit; var reforigine = vm.RefOrigine; if (vm.Images != null) { foreach (var image in vm.Images) { byte[] fileData = null; // read file to byte array using (var binaryReader = new BinaryReader(image.OpenReadStream())) { fileData = binaryReader.ReadBytes((int)image.Length); } } } return response; } public class ViewModel { public string FamilleProduit { get; set; } public string RefOrigine { get; set; } public List<IFormFile> Images { get; set; } }

我正在用Postman和i POST测试2个文本(FamilleProduit和RefOrigine)和2个带有"multipart/form-data"的文件(2个图像). 我完美地得到了2个文本，但是图像"字段每次都为空.

I'm testing with Postman and i POST 2 text (FamilleProduit & RefOrigine) and 2 files (2 images) with "multipart/form-data". I get the 2 texts perfectly but Images field is null everytime.

谢谢， 特里斯坦.

推荐答案

您可以使用内置类IFormFile轻松处理文件上传.要将其与JSON一起使用，您可以创建自定义模型联编程序，并将其结合到DTO对象中:

You can use built-in class IFormFile to easily work with file upload. To use it together with JSON you may create custom model binder and combine it together in DTO object:

public class ViewModel { [ModelBinder(BinderType = typeof(FormDataJsonBinder))] public DataModel Data { get;set; } public List<IFormFile> Images { get; set; } } public class FormDataJsonBinder : IModelBinder { public Task BindModelAsync(ModelBindingContext bindingContext) { if(bindingContext == null) { throw new ArgumentNullException(nameof(bindingContext)); } string fieldName = bindingContext.FieldName; var valueProviderResult = bindingContext.ValueProvider.GetValue(fieldName); if(valueProviderResult == ValueProviderResult.None) { return Task.CompletedTask; } else { bindingContext.ModelState.SetModelValue(fieldName, valueProviderResult); } string value = valueProviderResult.FirstValue; if(string.IsNullOrEmpty(value)) { return Task.CompletedTask; } try { object result = JsonConvert.DeserializeObject(value, bindingContext.ModelType); bindingContext.Result = ModelBindingResult.Success(result); } catch(JsonException) { bindingContext.Result = ModelBindingResult.Failed(); } return Task.CompletedTask; } }

然后您可以在控制器中使用它:

Then you can work with it in your controller:

[HttpPost] public IActionResult Create(ViewModel vm) { var data = vm.Data; if (vm.Images != null) { foreach(var image in vm.Images) { byte[] fileData = null; // read file to byte array using (var binaryReader = new BinaryReader(image.OpenReadStream())) { fileData = binaryReader.ReadBytes((int)image.Length); } } } }