如何检查自定义模型粘合剂内属性特性 [英] How to check for a property attribute inside a custom model binder
问题描述
我要强制在我的系统的所有日期是有效的,而不是在未来,因此我执行这些自定义模型绑定内:
I want to enforce that all dates in my system are valid and not in the future, so I enforce them inside the custom model binder:
class DateTimeModelBinder : IModelBinder {
public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext) {
var value = bindingContext.ValueProvider.GetValue(bindingContext.ModelName);
try {
var date = value.ConvertTo(typeof(DateTime), CultureInfo.CurrentCulture);
// Here I want to ask first if the property has the FutureDateAttribute
if ((DateTime)date > DateTime.Today) {
bindingContext.ModelState.AddModelError(bindingContext.ModelName, "No se puede indicar una fecha mayor a hoy");
}
return date;
}
catch (Exception) {
bindingContext.ModelState.AddModelError(bindingContext.ModelName, "La fecha no es correcta");
return value.AttemptedValue;
}
}
}
现在,对于少数例外我想允许一些日期是将来的
Now, for a few exceptions I want to allow some dates to be in the future
[Required]
[Display(Name = "Future Date")]
[DataType(DataType.DateTime)]
[FutureDateTime] <-- this attribute should allow the exception
public DateTime FutureFecha { get; set; }
这是属性
[AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = false)]
public class FutureDateTimeAttribute : Attribute {
}
现在,问题:?如何检查属性是 BindModel
方法内present
Now, the question: How can I check that the attribute is present inside the BindModel
method?
推荐答案
在的结合的模型的性质,我们必须通过访问业主:
During binding of the Model properties, we have access to property owner via:
bindingContext.ModelMetadata.ContainerType
。
所以,下面的代码片段应该给你的变量 hasAttribute
设置为true的 FutureFecha 的属性
So the below snippet should give you variable hasAttribute
set to true for FutureFecha property
var holderType = bindingContext.ModelMetadata.ContainerType;
if (holderType != null)
{
var propertyType = holderType.GetProperty(bindingContext.ModelMetadata.PropertyName);
var attributes = propertyType.GetCustomAttributes(true);
var hasAttribute = attributes
.Cast<Attribute>()
.Any(a => a.GetType().IsEquivalentTo(typeof (FutureDateTime)));
if(hasAttribute) ...
}
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