RuleUniqueValueAttribute(String, DefaultContexts, String) Constructor

Initializes a new instance of the RuleUniqueValueAttribute class.

Namespace: DevExpress.Persistent.Validation

Assembly: DevExpress.Persistent.Base.v24.1.dll

NuGet Package: DevExpress.Persistent.Base

Declaration

C#

public RuleUniqueValueAttribute(
    string id,
    DefaultContexts targetContexts,
    string messageTemplate
)

VB.NET

Public Sub New(
    id As String,
    targetContexts As DefaultContexts,
    messageTemplate As String
)

Parameters

Name	Type	Description
id	String	A string value representing the current rule identifier. You can pass an empty value as the id parameter. An appropriate identifier will begenerated automatically, and set for the ID property of the Validation | Rules | Rule node in the Application Model.
targetContexts	DefaultContexts	A DefaultContexts enumeration value that specifies a context for checking the current rule. This value is set for the RuleBaseAttribute.TargetContextIDs property.
messageTemplate	String	A string value representing information defining the current rule. This value is set for the RuleBaseAttribute.CustomMessageTemplate property.

Remarks

If you are going to use a default message template for the rule, use a constructor without the messageTemplate parameter.

Related GitHub Examples

The following code snippet (auto-collected from DevExpress Examples) contains a reference to the RuleUniqueValueAttribute(String, DefaultContexts, String) constructor.

Note

The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.

C#

xaf-how-to-implement-a-security-system-user-based-on-an-existing-business-class/CS/EmployeeAsUserExample.Module/BusinessObjects/Employee.cs#L31

[RuleRequiredField("EmployeeUserNameRequired", DefaultContexts.Save)]
[RuleUniqueValue("EmployeeUserNameIsUnique", DefaultContexts.Save,
    "The login with the entered user name was already registered within the system.")]

VB.NET

xaf-how-to-implement-a-security-system-user-based-on-an-existing-business-class/VB/EmployeeAsUserExample.Module/BusinessObjects/Employee.vb#L40

    <RuleRequiredField("EmployeeUserNameRequired", DefaultContexts.Save),
RuleUniqueValue("EmployeeUserNameIsUnique", DefaultContexts.Save,
"The login with the entered user name was already registered within the system.")>