RuleCriteriaAttribute Class
Defines a validation rule that demands an object of the target type satisfy a specified criterion.
Namespace: DevExpress.Persistent.Validation
Assembly:
DevExpress.Persistent.Base.v24.2.dll
Declaration
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Property | AttributeTargets.Interface, AllowMultiple = true)]
public class RuleCriteriaAttribute :
RuleBaseAttribute,
IRuleCriteriaProperties,
IRuleCollectionPropertyProperties,
IRuleBaseProperties
<AttributeUsage(AttributeTargets.Class Or AttributeTargets.Property Or AttributeTargets.Interface, AllowMultiple:=True)>
Public Class RuleCriteriaAttribute
Inherits RuleBaseAttribute
Implements IRuleCriteriaProperties,
IRuleCollectionPropertyProperties,
IRuleBaseProperties
Apply this attribute to a business class to define a criterion that must be satisfied by this class’ objects. Use the criteria parameter to specify the required criterion. To learn how to write criteria correctly, refer to the Ways to Build Criteria topic. In criteria, you can use Function Criteria Operators. For instance, the “Today = LocalDateTimeToday()” criterion means that the Today property must be set to the current date.
When applying this attribute, use common parameters that are inherited from the RuleBaseAttribute class, in addition to the criteria parameter.
Note that when you need to check whether a property is specified, use the RuleRequiredFieldAttribute, rather than the RuleCriteriaAttribute. However, there are scenarios when you need to use the RuleCriteriaAttribute for this purpose. The following code demonstrates one of them. The Address objects are related to the User and Client objects by the One-To-One relationship. But, the Address object must not have the House property set to 0 when it is assigned to the Client objects.
[DefaultClassOptions]
public class Address : BaseObject {
public virtual string Street { get; set; }
public virtual int House { get; set; }
}
[DefaultClassOptions]
[RuleCriteria("", DefaultContexts.Save, "ClientAddress.House != 0",
"House should not be 0", SkipNullOrEmptyValues = false)]
public class Client : BaseObject {
public virtual string ClientName { get; set; }
public virtual Address ClientAddress { get; set; }
}
[DefaultClassOptions]
public class User : BaseObject {
public virtual string UserName { get; set; }
public virtual Address UserAddress { get; set; }
}
// Make sure that you use options.UseChangeTrackingProxies() in your DbContext settings.
[DefaultClassOptions]
public class Address : BaseObject {
public Address(Session session) : base(session) { }
private string street;
public string Street {
get { return street; }
set { SetPropertyValue(nameof(Street), ref street, value); }
}
private int house;
public int House{
get { return house; }
set { SetPropertyValue(nameof(House), ref house, value); }
}
}
[DefaultClassOptions]
[RuleCriteria("", DefaultContexts.Save, "ClientAddress.House != 0",
"House should not be 0", SkipNullOrEmptyValues = false)]
public class Client : BaseObject {
public Client(Session session) : base(session) { }
string fClientName;
public string ClientName {
get { return fClientName; }
set { SetPropertyValue(nameof(ClientName), ref fClientName, value); }
}
Address fClientAddress;
public Address ClientAddress {
get { return fClientAddress; }
set { SetPropertyValue(nameof(ClientAddress), ref fClientAddress, value); }
}
}
[DefaultClassOptions]
public class User : BaseObject {
public User(Session session) : base(session) { }
string fUserName;
public string UserName {
get { return fUserName; }
set { SetPropertyValue(nameof(UserName), ref fUserName, value); }
}
Address fUserAddress;
public Address UserAddress {
get { return fUserAddress; }
set { SetPropertyValue(nameof(UserAddress), ref fUserAddress, value); }
}
}
<DefaultClassOptions> _
Public Class Address
Inherits BaseObject
Public Sub New(ByVal session As Session)
MyBase.New(session)
End Sub
Private fstreet As String
Public Property Street() As String
Get
Return fstreet
End Get
Set
SetPropertyValue(NameOf(Street), fstreet, Value)
End Set
End Property
Private fhouse As Integer
Public Property House() As Integer
Get
Return fhouse
End Get
Set
SetPropertyValue(NameOf(House), fhouse, Value)
End Set
End Property
End Class
<DefaultClassOptions, RuleCriteria("", DefaultContexts.Save, "ClientAddress.House != 0", _
"House should not be 0", SkipNullOrEmptyValues := False)> _
Public Class Client
Inherits BaseObject
Public Sub New(ByVal session As Session)
MyBase.New(session)
End Sub
Public Property ClientName() As String
Get
Return fClientName
End Get
Set(ByVal value as String)
SetPropertyValue(NameOf(ClientName), fClientName, value)
End Set
End Property
Private fClientName As String
Public Property ClientAddress() As Address
Get
Return fClientAddress
End Get
Set(ByVal value as Address)
SetPropertyValue(NameOf(ClientAddress), fClientAddress, value)
End Set
End Property
Private fClientAddress As Address
End Class
<DefaultClassOptions> _
Public Class User
Inherits BaseObject
Public Sub New(ByVal session As Session)
MyBase.New(session)
End Sub
Public Property UserName() As String
Get
Return fUserName
End Get
Set(ByVal value as String)
SetPropertyValue(NameOf(UserName), fUserName, value)
End Set
End Property
Private fUserName As String
Public Property UserAddress() As Address
Get
Return fUserAddress
End Get
Set(ByVal value as Address)
SetPropertyValue(NameOf(UserAddress), fUserAddress, value)
End Set
End Property
Private fUserAddress As Address
End Class
In the code above, the RuleCriteriaAttribute has the RuleBaseAttribute.SkipNullOrEmptyValues parameter set to false. This is required, so that the rule defined by this attribute is checked when the target property is not specified.
The rule generated by the RuleCriteriaAttribute will be loaded to the Application Model‘s IModelValidationRules node. So, you can customize this rule via the Model Editor. In addition, you can create new rules in the Model Editor as well. For details, refer to the Implement Property Value Validation topic.
You can see examples of using the RuleCriteria and other validation attributes in the Validation section of the FeatureCenter demo. This demo is located in the %PUBLIC%\Documents\DevExpress Demos 24.2\Components\XAF\FeatureCenter.NETFramework.XPO folder, by default.
See Also