我对使用WinForms应用程序和实体框架5设置客户端验证很感兴趣。我知道我可以实现IValidatableObject接口来执行,也有可能需要为每个实体执行自定义验证。
但是,由于我使用的是WinForms,所以我想使用ErrorProvider在用户填写表单时出现验证错误时向用户显示一个很好的通知。是否可以使用IValidatableObject接口实现此功能,或者为了让ErrorProvider正常工作,我还需要在实体上实现IDataErrorInfo接口吗?
如果你对此有任何更好的替代方案,请让我知道,我也会很乐意调查的。
发布于 2013-12-05 00:56:22
假设您有一个名为Car
的实体,该类包含一个属性,该属性需要经过验证的。
public class Car
{
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
// Accepted values have to be between 1 and 5.
public int NeedToBeValidatedRange { get; set; }
}
您必须为所有实体创建一个基类,在我的示例中,我将其命名为Entity。
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.ComponentModel.DataAnnotations;
using System.Linq;
/// This is the base class for all entities and it provide a change notfication.
public abstract class Entity : INotifyPropertyChanged
{
// Event fired when the property is changed!
public event PropertyChangedEventHandler PropertyChanged;
/// Called when int property in the inherited class is changed for ther others properties like (double, long, or other entities etc,) You have to do it.
protected void HandlePropertyChange(ref int value, int newValue, string propertyName)
{
if (value != newValue)
{
value = newValue;
this.Validate(propertyName);
this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
/// Validate the property
/// <returns>
/// The list of validation errors
/// </returns>
private ICollection<ValidationResult> PropertyValidator(string propertyName)
{
var validationResults = new Collection<ValidationResult>();
PropertyDescriptor property = TypeDescriptor.GetProperties(this)[propertyName];
Validator.TryValidateProperty(
property.GetValue(this),
new ValidationContext(this, null, null) { MemberName = propertyName },
validationResults);
return validationResults;
}
/// Validates the given property and return all found validation errors.
private void Validate(string propName)
{
var validationResults = this.PropertyValidator(propName);
if (validationResults.Count > 0)
{
var validationExceptions = validationResults.Select(validationResult => new ValidationException(validationResult.ErrorMessage));
var aggregateException = new AggregateException(validationExceptions);
throw aggregateException;
}
}
}
现在你应该修改Car类,它应该是这样的:
public class Car : Entity
{
private int id;
private int needToBeValidatedRange;
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id
{
get
{
return this.id;
}
set
{
this.HandlePropertyChange(ref this.id, value, "Id");
}
}
[Range(1, 5)]
public int NeedToBeValidatedRange
{
get
{
return this.needToBeValidatedRange;
}
set
{
this.HandlePropertyChange(ref this.needToBeValidatedRange, value, "NeedToBeValidatedRange ");
}
}
}
在用户界面中的某处,您正在创建汽车实体:
Car car1 = new Car();
car1.NeedToBeValidatedRange = 3; // This will work!
Car car2 = new Car();
car2.NeedToBeValidatedRange = 6; // This will throw ValidationException
发布于 2013-12-02 05:44:09
有两种选择:
有关使用IValidateObject扩展poco类以及在调用保存更改时处理验证错误的示例,请参阅以下示例。
https://stackoverflow.com/questions/14451413
复制相似问题