DisplayColumnAttribute Class

Definition

Namespace:

System.ComponentModel.DataAnnotations

Assembly:

System.ComponentModel.Annotations.dll

Source:

DisplayColumnAttribute.cs

Specifies the column that is displayed in the referred table as a foreign-key column.

public ref class DisplayColumnAttribute : Attribute

[System.AttributeUsage(System.AttributeTargets.Class, AllowMultiple=false, Inherited=true)]
public class DisplayColumnAttribute : Attribute

[<System.AttributeUsage(System.AttributeTargets.Class, AllowMultiple=false, Inherited=true)>]
type DisplayColumnAttribute = class
    inherit Attribute

Public Class DisplayColumnAttribute
Inherits Attribute

Inheritance

Object

Attribute

DisplayColumnAttribute

Attributes

AttributeUsageAttribute

Examples

The following example shows how to use the DisplayColumnAttribute attribute. The example performs the following tasks:

• Implements metadata partial classes for the Address and Customer tables, which are parent tables for the CustomerAddress table.

• Applies the DisplayColumnAttribute attribute to the Address metadata partial class to specify the following:

  • The City column from the Address table (the parent table) is displayed as the foreign-key column in the CustomerAddress child table.

  • The PostalCode column from the Address table (the parent table) is used for sorting the Address selection box in the CustomerAddress child table.

  • The sort order is set to ascending.

The example applies the DisplayColumnAttribute attribute to the Customer metadata partial class to specify that the LastName column in displayed as the foreign-key column for the CustomerAddress table.

using System;
using System.Web.DynamicData;
using System.ComponentModel.DataAnnotations;
using System.Globalization;

[DisplayColumn("City", "PostalCode", false)]
public partial class Address
{
}

[DisplayColumn("LastName")]
public partial class Customer
{
}

Imports System.Web.DynamicData
Imports System.ComponentModel.DataAnnotations
Imports System.Globalization

<DisplayColumn("City", "PostalCode", False)> _
Partial Public Class Address

End Class

<DisplayColumn("LastName")> _
Public Partial Class Customer

End Class

To compile the example, you need the following:

• Any edition of Visual Studio 2010 or later.

• The AdventureWorksLT sample database. For information about how to download and install the SQL Server sample database, see Microsoft SQL Server Product Samples: Database on GitHub. Make sure that you install the correct version of the sample database for the version of SQL Server that you are running.

• A dynamic data-driven Web site. This enables you to create a data context for the database and to create the class that contains the data field to customize. For more information, see Walkthrough: Creating a New Dynamic Data Web Site using Scaffolding.

Remarks

When a column in a table contains a foreign key, Dynamic Data infers the display value for that column from the referenced table. By default, the first column of the referenced table whose type is string (or text) is used. The DisplayColumnAttribute attribute enables you to change this default behavior and to specify a different parent table column to use as the column for the foreign key field.

When you apply this attribute, you must adhere to the following usage constraints:

• The attribute can only be applied to a class.

• The attribute can be inherited by derived classes.

• The attribute can be applied only one time.

Constructors

DisplayColumnAttribute(String, String, Boolean)	Initializes a new instance of the DisplayColumnAttribute class by using the specified display column, and the specified sort column and sort order.
DisplayColumnAttribute(String, String)	Initializes a new instance of the DisplayColumnAttribute class by using the specified display and sort columns.
DisplayColumnAttribute(String)	Initializes a new instance of the DisplayColumnAttribute class by using the specified column.

Properties

DisplayColumn	Gets the name of the column to use as the display field.
SortColumn	Gets the name of the column to use for sorting.
SortDescending	Gets a value that indicates whether to sort in descending or ascending order.
TypeId	When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute)

Methods

Equals(Object)	Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute)
GetHashCode()	Returns the hash code for this instance. (Inherited from Attribute)
GetType()	Gets the Type of the current instance. (Inherited from Object)
IsDefaultAttribute()	When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute)
Match(Object)	When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
ToString()	Returns a string that represents the current object. (Inherited from Object)