This documentation is archived and is not being maintained.

DisplayFormatAttribute Class

Specifies how data fields are displayed and formatted by ASP.NET Dynamic Data.


Namespace:  System.ComponentModel.DataAnnotations
Assembly:  System.ComponentModel.DataAnnotations (in System.ComponentModel.DataAnnotations.dll)

[AttributeUsageAttribute(AttributeTargets.Property|AttributeTargets.Field, AllowMultiple = false)]
public class DisplayFormatAttribute : Attribute

The DisplayFormatAttribute type exposes the following members.

Public methodDisplayFormatAttributeInitializes a new instance of the DisplayFormatAttribute class.

Public propertyApplyFormatInEditModeGets or sets a value that indicates whether the formatting string that is specified by the DataFormatString property is applied to the field value when the data field is in edit mode.
Public propertyConvertEmptyStringToNullGets or sets a value that indicates whether empty string values ("") are automatically converted to null when the data field is updated in the data source.
Public propertyDataFormatStringGets or sets the display format for the field value.
Public propertyHtmlEncodeGets or sets a value that indicates whether the field should be HTML-encoded.
Public propertyNullDisplayTextGets or sets the text that is displayed for a field when the field's value is null.
Public propertyTypeIdWhen implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)

Public methodEqualsInfrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetHashCodeReturns the hash code for this instance. (Inherited from Attribute.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodIsDefaultAttributeWhen overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)
Public methodMatchWhen overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)

Explicit interface implemetationPrivate method_Attribute.GetIDsOfNamesMaps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoRetrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoCountRetrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.InvokeProvides access to properties and methods exposed by an object. (Inherited from Attribute.)

When you apply this attribute to a data field, you must follow the guidelines for the use of the attributes. For more information, see ASP.NET Dynamic Data Guidelines.

See an online example of this feature: Run.

The following example shows how to use the DisplayFormatAttribute to customize formatting for a data field. The example performs the following steps:

  • Implements a metadata partial class and an associated metadata class.

  • In the associated metadata class, it applies the DisplayFormatAttribute attribute to specify the following results:

    • Display the text "[Null]" when a data field is empty.

    • Display currency data in locale specific currency format.

    • Display date information in short format (mm/dd/yy). This format also applies in edit mode.

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

public partial class Product


public class ProductMetaData

    // Applying DisplayFormatAttribute
    // Display the text [Null] when the data field is empty.
    // Also, convert empty string to null for storing.
    [DisplayFormat(ConvertEmptyStringToNull = true, NullDisplayText = "[Null]")]
    public object Size;

    // Display currency data field in the format $1,345.50.
    public object StandardCost;

    // Display date data field in the short format 11/12/08.
    // Also, apply format in edit mode.
    [DisplayFormat(ApplyFormatInEditMode=true, DataFormatString = "{0:d}")]
    public object SellStartDate;

To compile the example, you need the following:

  • Microsoft Visual Studio 2008 Service Pack 1 or Visual Web Developer 2008 Express Edition Service Pack 1.

  • 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 the CodePlex site. Make sure that you install the correct version of the sample database for the version of SQL Server that you are running (Microsoft SQL Server 2005 or Microsoft SQL Server 2008).

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

.NET Framework

Supported in: 4, 3.5 SP1

.NET Framework Client Profile

Supported in: 4

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.