blocks|key|2831845|text|有两种选择：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2831846|2831847|使用IValidateObject和IdataErrorInfo扩展poco类，并在验证方法中引发ui错误。|unordered-list-item|2831848|在调用保存更改时捕获验证错误，并根据生成验证错误的实体字段直接调用ErrorProvider。|2831849|2831850|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。|2831851|2831852|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|O|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|P|8|@]|9|@]|A|$]]|$1|F|3|G|5|E|7|Q|8|@]|9|@]|A|$]]|$1|H|3|-4|5|6|7|R|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|S|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|T|8|@]|9|@]|A|$]]|$1|L|3|-4|5|6|7|U|8|@]|9|@]|A|$]]]|M|$]]

There are two choices:

<ul>
<li>extend your poco classes with IValidateObject and IdataErrorInfo and raise the ui error in the validation method.</li>
<li>catch the validation error when save changes is called and invoke ErrorProvider directly depending on which entity field generates the validation error.</li>
</ul>

See the following for examples of extending poco classes with IValidateObject and handling validation errors when save changes are called.

<a href="http://msdn.microsoft.com/en-us/data/gg193959.aspx">http://msdn.microsoft.com/en-us/data/gg193959.aspx</a>

blocks|key|2831878|text|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。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|BOLD|entityRanges|data|2831879|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;+}
}|code-block|syntax|javascript|2831880|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。|2831881|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;
++++}
++}
}|2831882|现在你应该修改Car类，它应该是这样的：|2831883|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+");
++++}
++}
}|2831884|在用户界面中的某处，您正在创建汽车实体：|2831885|Car+car1+=+new+Car();
car1.NeedToBeValidatedRange+=+3;++//+This+will+work!

Car+car2+=+new+Car();
car2.NeedToBeValidatedRange+=+6;++//+This+will+throw+ValidationException|2831886|2831887|WPF支持非常好的ValidationException.|unordered-list-item|2831888|Winforms，部分支持ValidationException，但是现在您可以自由地处理这个问题。|2831889|2831890|entityMap^0|8|3|V|3|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|16|8|@$9|17|A|18|B|C]|$9|19|A|1A|B|D]]|E|@]|F|$]]|$1|G|3|H|5|I|7|1B|8|@]|E|@]|F|$J|K]]|$1|L|3|M|5|6|7|1C|8|@]|E|@]|F|$]]|$1|N|3|O|5|I|7|1D|8|@]|E|@]|F|$J|K]]|$1|P|3|Q|5|6|7|1E|8|@]|E|@]|F|$]]|$1|R|3|S|5|I|7|1F|8|@]|E|@]|F|$J|K]]|$1|T|3|U|5|6|7|1G|8|@]|E|@]|F|$]]|$1|V|3|W|5|I|7|1H|8|@]|E|@]|F|$J|K]]|$1|X|3|-4|5|6|7|1I|8|@]|E|@]|F|$]]|$1|Y|3|Z|5|10|7|1J|8|@]|E|@]|F|$]]|$1|11|3|12|5|10|7|1K|8|@]|E|@]|F|$]]|$1|13|3|-4|5|6|7|1L|8|@]|E|@]|F|$]]|$1|14|3|-4|5|6|7|1M|8|@]|E|@]|F|$]]]|15|$]]

Lets say you have an Entity called <code>Car</code> and this class contains an property which need be validated.

<pre><code>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; }
}
</code></pre>

You have to create a base class for all your entites in my example I will called Entity.

<pre><code>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 
 /// &lt;returns&gt;
 /// The list of validation errors
 /// &lt;/returns&gt;
 private ICollection&lt;ValidationResult&gt; PropertyValidator(string propertyName)
 {
 var validationResults = new Collection&lt;ValidationResult&gt;();
 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 &gt; 0)
 {
 var validationExceptions = validationResults.Select(validationResult =&gt; new ValidationException(validationResult.ErrorMessage));
 var aggregateException = new AggregateException(validationExceptions);
 throw aggregateException;
 }
 }
}
</code></pre>

Now you shall modfiy the Car class and it should be like that:

<pre><code>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 ");
 }
 }
}
</code></pre>

Somewhere in the user interface you are creating the car entities:

<pre><code>Car car1 = new Car();
car1.NeedToBeValidatedRange = 3; // This will work!

Car car2 = new Car();
car2.NeedToBeValidatedRange = 6; // This will throw ValidationException
</code></pre>

<ul>
<li>WPF support very good ValidationException.</li>
<li>Winforms support partially ValidationException but now you are free how to handle this.</li>
</ul>

I'm interested in setting up client side validation using a WinForms application and Entity Framework 5. I understand that there's the IValidatableObject interface that I can implement to perform and custom validation that I may need for each entity. 

However, since I'm using WinForms I'd like to use the ErrorProvider to present the user with a nice notification when there is a validation error as they fill out a form. Is this functionality able to be achieved using the IValidatableObject interface or would I need to implement the IDataErrorInfo interface on my entities as well in order to have the ErrorProvider work properly?

If you have any other suggestions on a better alternative to this please let me know and I'll gladly look into that as well.

Entity Framework UI Validation using WinForms

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IVa...

问使用WinForms进行实体框架UI验证
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