测试用于文件上载的Web API,有一个像这样的简单视图模型：
public class TestModel {
public string UserId {get;set;}
public HttpPostedFileBase ImageFile {get;set;}
}
用于方法：
[HttpPost] public void Create(TestModel model)
当我尝试将多部分/表单数据编码的表单发布到操作时,我收到此异常：
System.InvalidOperationException: No MediaTypeFormatter is available to read an object of type 'TestModel' from content with media type 'multipart/form-data'. at System.Net.Http.HttpContentExtensions.ReadAsAsync[T](HttpContent content,Type type,IEnumerable`1 formatters,IFormatterLogger formatterLogger) at System.Net.Http.HttpContentExtensions.ReadAsAsync(HttpContent content,IFormatterLogger formatterLogger) at System.Web.Http.ModelBinding.FormatterParameterBinding.ReadContentAsync(HttpRequestMessage request,IFormatterLogger formatterLogger) at System.Web.Http.ModelBinding.FormatterParameterBinding.ExecuteBindingAsync(ModelMetadataProvider MetadataProvider,HttpActionContext actionContext,CancellationToken cancellationToken) at System.Web.Http.Controllers.HttpActionBinding.<>c__DisplayClass1.<ExecuteBindingAsync>b__0(HttpParameterBinding parameterBinder) at System.Linq.Enumerable.WhereSelectArrayIterator`2.MoveNext() at System.Threading.Tasks.TaskHelpers.IterateImpl(IEnumerator`1 enumerator,CancellationToken cancellationToken)
这适用于默认的MVC模型绑定器,但显然不适用于Web API.发现一些人提到你在上传文件时不能使用视图模型,只是将数据分成两个调用.这对我不起作用,因为我需要发布其他字段才能真正对上传的文件做些什么.有办法实现这个目标吗？
解决方法
看我原来的答案
https://stackoverflow.com/a/12603828/1171321
https://stackoverflow.com/a/12603828/1171321
基本上在我的博客文章和TryValidateProperty()建议中结合我的方法来维护模型验证注释.
编辑：
我继续在博客文章中对代码进行了代码增强.我将很快发布这个更新的代码.这是一个简单的示例,它验证每个属性并允许您访问结果数组.只是一种方法的样本
public class FileUpload<T>
{
private readonly string _RawValue;
public T Value { get; set; }
public string FileName { get; set; }
public string MediaType { get; set; }
public byte[] Buffer { get; set; }
public List<ValidationResult> ValidationResults = new List<ValidationResult>();
public FileUpload(byte[] buffer,string mediaType,string fileName,string value)
{
Buffer = buffer;
MediaType = mediaType;
FileName = fileName.Replace("\"","");
_RawValue = value;
Value = JsonConvert.DeserializeObject<T>(_RawValue);
foreach (PropertyInfo Property in Value.GetType().GetProperties())
{
var Results = new List<ValidationResult>();
Validator.TryValidateProperty(Property.GetValue(Value),new ValidationContext(Value) {MemberName = Property.Name},Results);
ValidationResults.AddRange(Results);
}
}
public void Save(string path,int userId)
{
if (!Directory.Exists(path))
{
Directory.CreateDirectory(path);
}
var SafeFileName = Md5Hash.GetSaltedFileName(userId,FileName);
var NewPath = Path.Combine(path,SafeFileName);
if (File.Exists(NewPath))
{
File.Delete(NewPath);
}
File.WriteAllBytes(NewPath,Buffer);
var Property = Value.GetType().GetProperty("FileName");
Property.SetValue(Value,SafeFileName,null);
}
}
