ASP.NET Web API中的action参数类型可以分为简单类型和复杂类型。HttpResponseMessage Put(int id, Product item)id是int类型,是简单类型,item是Product类型,是复杂类型。简单类型实参值从哪里读取呢?--一般 ...
get='_blank'>ASP.NET Web API中的action参数类型可以分为简单类型和复杂类型。HttpResponseMessage Put(int id, Product item)id是int类型,是简单类型,item是Product类型,是复杂类型。简单类型实参值从哪里读取呢?所谓的简单类型包括哪些呢?复杂类型实参值从哪里读取呢?复杂类型实参值是否可以从URI中获取呢?→ 有这样的一个类
public class Shape{ public double Width{get;set;} public double Length{get;set;}}
public HttpResponseMessage Get([FromUri] Shape shape)→ 客户端就可以放在查询字符串中传...api/products/?Width=88&Length=199简单类型可以从请求的body中获取吗?→ action方法public HttpResponseMessage Post([FromBody]
string name){...}→
前端请求中Content-Type:applicaiton/json"hello world"API服务端会根据Content-Type的值选择合适的媒体类型。复杂类型是否可以从uri中的字符串获取呢?api/products/?shape=188,80
如何把uri中查询字符串中shape的字段值,即以逗号分割的字符串转换成Shape类实例呢?public HttpResponseMessage Get(Shape shape)→ 客户端api/products/?shape=188,80是否可以通过Model Binder来实现自定义参数绑定过程呢?→ 自定义一个Model Binder
public class ShapeModelBinder : IModelBinder{ private static ConcurrentDictionary<string, Shape> _shapes = new ConcurrentDictionary<string, Shape>(StringComparer.OrdinalIgnoreCase); static ShapeModelBinder() { _shapes["shape1"] = new Shape(){Width= 10, Length = 20}; _shapes["shape2"] = new Shape(){Width=12, Length = 22 }; } public bool BindModel(HttpActionContext actionContext, ModelBindingContect biningContext) { if(bindingContext.ModelType != typeof(Shape)) { return false; } ValueProviderResult val = bindingContext.ValueProvider.GetValue(bidingContext.ModelName); if(val == null) { return false; } string key = val.RawValue as string; if(key == null){ bdingContext.ModelState.AddModelError(bindingContext.ModelName, "值类型错误"); return false; } Shape shape; if(_shapes.TryGetValue(key, out shape) || Shape.TryParse(key, shape)) { bindingContext.Model = result; return true; } bindingContext.ModelState.AddModelError(bindingContext.ModelName, "无法把字符串转换成Shape"); return false; }}
→ 使用自定义的Model Binder可以运用在action中:public HttpResposneMessage Get([ModelBinder(typeof(ShapeModelBinder))] Shape shape);可以放在模型上:
[ModelBinder(typeof(Shape))]public class Shape{}
public HttpResponseMessage Get([ModelBinder] Shape shape);是否可以通过Value Provider来自定义参数绑定过程呢?比如,从前端cookie中获取值,自定义一个Value Provider.
public class MyCookieValueProvider : IValueProvider{ private Dictionary<string, string> _values; public MyCookieValueProvider(HttpActionContext actionContext) { if(actionContext == null) { throw new ArgumentNullException("actionContext"); } _values = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase); foreach(var cookie in actionContext.Request.Headers.GetCookies()) { foreach(CookieState state in cookie.Cookies) { _values[state.Name] = state.Value; } } } public bool COntainsPrefix(string prefix) { return _values.keys.Contains(prefix); } public ValueProviderResult GetValue(string key) { string value; if(_values.TryGetValue(key, out value)) { return new ValueProviderResult(value, value, CultureInfo.InvariantCulture); } return null; }}
public HttpResponseMessage Get([ValueProvider(typeof(MyCookieValueProviderFactory))] Shape shape);
是否可以通过HttpParameterBinding实现参数绑定自定义呢?ModelBinderAttribute继承于ParameterBindingAttribute.
public abstract class ParameterBindingAttribute : Attribute{ public abstract HttpParameterBinding GetBinding(HttpParameterDescriptor parameter);}
假设,需要从前端请求的if-match和if-none-match字段获取ETag值。
public class ETag{ public string Tag{get;set;}}
如何使用自定义的HttpParameterBinding呢?public HttpResponseMessage Get([IfNoneMatch] ETag etag)还需要在全局注册:
config.ParameterBindingRules.Add(p => { if(p.ParameterType == typeof(ETag) && p.ActionDescriptor.SupportedHttpMethods.Contains(HttpMethod.Get)) { return new ETagParameterBinding(p, ETagMatch.IfNoneMatch); } else { return null; }})
原标题:ASP.NET Web API中的参数绑定总结
关键词:ASP.NET
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