,所以我有ASP.NET核心应用程序Angular2。现在,我想上传图像,如果我将其上传为字节[],则设法这样做。但是,我无法检查文件是否是后端中的图像是否确实是图像,所以我尝试寻找其他解决方案。我找到了有关文件上传的博客:https://devblog.dymel.pl/2l/2016/09/02/upload---file-image-angular2-aspnetcore/它对我不起作用...
用于文件上传我使用angular2库 angular2-image-upload ,所以我的html图像上传的一部分看起来像这样:
<image-upload [max]="1" [buttonCaption]="'Browse'" [preview]="false" (change)="onFileChange($event)"></image-upload>
<button (click)="onSaveChanges()" class="btn btn-primary float-left" type="submit">Save</button>
然后我的angular2部分看起来像这样:
onFileChange(event: any) {
this.file = event.target.files[0];
if (event.target.files && this.file) {
var reader = new FileReader();
reader.onload = (event: any) => {
this.profilePicture = event.target.result;
}
reader.readAsDataURL(this.file);
}
}
onSaveChanges() {
this.isSaving = true;
this.country = this.state.user.country;
this.userService.userChange(this.firstName, this.lastName, this.country, this.file, this.currentPassword, this.newPassword).subscribe(success => {
this.state.user.profilePicture = this.profilePicture;
this.state.user.firstName = this.firstName;
this.state.user.lastName = this.lastName;
this.isSaving = false;
this.passwordError = false;
this.isSuccessful = true;
this.currentPassword = '';
this.newPassword = '';
this.newPasswordRepeat = '';
}, error => {
this.isSaving = false;
this.passwordError = true;
this.passwordErrorMessage = error._body;
});
}
我的angular2 api呼叫看起来像这样:
userChange(firstName: string, lastName: string, country: string, file: File, oldPassword: string, newPassword: string) {
let input = new FormData();
input.append("File", file);
var url = this.baseUrl + "updateUser";
return this.http.post(url, { FirstName: firstName, LastName: lastName, Country: country, File: input, OldPassword: oldPassword, NewPassword: newPassword });
}
我的ASP.NET核心控制器(请注意,我没有显示控制器的主体,因为它是无关的(:
[HttpPost]
public async Task<IActionResult> UpdateUser([FromBody]UserChange userChange)
{
}
UserChange类:
public class UserChange
{
public string FirstName { get; set; }
public string LastName { get; set; }
public string Country { get; set; }
public IFormFile File { get; set; }
public string OldPassword { get; set; }
public string NewPassword { get; set; }
}
问题是,当我提交图像时,我总是将我的userChange对象作为null。当我添加图像时,它像魅力有什么问题?为什么即使我传递了不是null的文件,我也会始终变得无效?我看到的另一件事是,当我将类型从iformfile更改为FormFile时,我的UserChange对象不再为空,而只有来自对象的文件参数是抛出此错误
'userChange.file.ContentDisposition'抛出了一个例外'System.NullReferenceException'
更新1
以某种方式,我设法使用以下答案将文件发送到ASP.NET控制器:使用ASP.NET Core Web API文件上传文件始终是无效的,但是我必须创建另一个没有参数的操作,但是如何发送在我的情况下,文件仍然未知...
我在想做类似的事情时找到了您的帖子,还开始使用angular2-image-upload库,但决定先尝试简单的方法。出于我的目的,我只需要字节[]图像文件(将尝试为下一个图像标题和字幕添加表单字段(,并在此处找到了Michael Dymel在此博客文章中提出的一些内容,这非常有用并使其正常工作。尽管您无法获得工作方法,但它对我有很大帮助。
我被解开的地方是正确的路由配置,并且有一段时间看起来我的文件在Angular Service上正确拾取了,但是当它到达"上传"控制器时是无效的。一旦我检查了上传服务的路径和控制器的[路由("/api/upload"(属性中定义的路径是相同的,所有这些属性都落在适当的位置,我能够成功上传。与您的问题略有不同,但这对我有用:
我的上传组件方法:
addFile(): void {
let fi = this.fileInput.nativeElement;
if (fi.files && fi.files[0]) {
let fileToUpload = fi.files[0];
if (fileToUpload) {
this.uploadService.upload(fileToUpload)
.subscribe(res => {
console.log(res);
});
}
else
console.log("FileToUpload was null or undefined.");
}
}
调用上传服务:
upload(fileToUpload: any) {
let input = new FormData();
input.append("fileForController", fileToUpload);
return this.http.post("/api/upload", input );
}
哪些张贴在我的ImagesController的"上传"操作中,看起来像这样(我将图像保存到数据库中,因此"路径"变量实际上是冗余的(。"图像"对象只是URL,标题,图像filecontent和字幕字段的简单模型:
[HttpPost]
[Route("/api/upload")]
public async Task<IActionResult> Upload(IFormFile fileForController)
{
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}
if (fileForController == null) throw new Exception("File is null");
if (fileForController.Length == 0) throw new Exception("File is empty");
var theImage = new Image();
var path = Path.Combine("~\ClientApp\app\assets\images\", fileForController.FileName);
theImage.Url = path + fileForController.FileName;
theImage.Title = fileForController.Name + "_" + fileForController.FileName;
theImage.Caption = fileForController.Name + " and then a Surprice Caption";
using (Stream stream = fileForController.OpenReadStream())
{
using (var reader = new BinaryReader(stream))
{
var fileContent = reader.ReadBytes((int)fileForController.Length);
theImage.ImageFileContent = fileContent;
_context.Images.Add(theImage);
try
{
await _context.SaveChangesAsync();
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
}
return Ok(theImage);
}
和我的HTML模板字段几乎完全像Michael Dymel的帖子一样:
<form action="gallery" name="fileUploadForm" method="post" enctype="multipart/form-data">
<div class="col-md-6">
<input #fileInput type="file" title="Choose Image to upload" />
<button (click)="addFile()" class="btn btn-success">Add</button>
</div>
</form>
您无法使用JSON向服务器发送二进制数据,因为JSON不支持二进制数据。
描述在这里
但是您可以尝试发送' Multipart/form-data '
示例代码.NET CORE API:
public class FormModel
{
public int Id { get; set; }
public string Title{ get; set; }
public string Url { get; set; }
public bool IsDeleted { get; set; }
public IFormFile File { get; set; }
}
[HttpPost]
public IActionResult Post([FromForm] FormModel formModel)
{
if (!ModelState.IsValid)
return BadRequest(ModelState);
//** your server side code **//
return Ok();
}
示例代码Angular HTTP发布您的表格数据:
const formData = new FormData();
formData.append('File', this.file[0] // your input file data);
formData.append('Id', this.Id.value // your form id value);
formData.append('Title', this.Title.value // your form title value);
formData.append('Url', this.Url.value // your form url value)
const options = new RequestOptions();
options.headers = new Headers();
options.headers.append('enctype', 'multipart/form-data');
this.http.post('your api url', formData, options) {
// your return value
}